OAS
Oasis Petroleum Inc. Common Stock
stock NASDAQ

Alternatively, with simple math:
* TFSA: Gross wage × (1 - tax rate now) × Growth
* RRSP: Gross wage × Growth × (1 - tax rate later)
* Non-reg: Gross wage × (1 - tax rate now) × Growth - 50% × Gains × tax rate later
Have growth be whatever multiplier you want. And by tax rate I of course mean Marginal Effective Tax Rate (miss me with that OAS clawback or GIS or well funded pension retort, just bake it in the METR)
As you mentioned, at equal METR (tax rate now = tax rate later) the TFSA will have the same after-tax returns as RRSP by commutativity of multiplication. The best non-reg can ever hope to achieve is approximating a TFSA if tax rate later is 0% (i.e. you realize capital gains strategically to always be below the effective taxable threshold) and you never receive taxable income from your investment from dividends or interest

I'm in a similar situation as you. We're at the point where we are slowing down RRSP contributions. It's still financially better to contribute to an RRSP, but I also want some flexibility. I think I'll need to burn down my RRSP starting at age 60 and delay CPP/OAS to 70... I still won't get OAS.
\- You're already going to be in the full OAS clawback group. It's probably too late for that in a good way. That $1.3M compounded to retirement will be pushing out $300 to $400k a year at 4% by the time you're thinking about OAS.
\- When you're doing the math on the cottage mortgage, keep in mind that you're paying the cottage interest with after tax money. So if you're paying 4%, you need to earn 8% on that money for it to be a wash.
\- When you're doing the math on registered vs. non-registered returns, keep in mind that you'll pay full tax on RRSP withdrawals (so something like 53%) but only half tax on unregistered returns, assuming they're capital gains. RRSP still comes out ahead. By my math, over a 20 year horizon and a 10% average return, you'll end up with 33% more money after tax from an RRSP vs. unregistered.

Read through some comments and a lot of great discussion here, but two things that I think need to be added
1) OAS Clawback is an issue, but you may already have hit a point of no return with that. You may run the numbers to find out that this is not a factor on your next dollar of gains anymore because you're already past the maximum clawback no matter what you do. I have a feeling with 1.3 million and 20 years of compounding, you're almost certainly at this point, but maybe you only have 9 years of compounding and start withdrawing on your kid's graduation day, so it's hard to say with the context here.
2) Churn matters. If you're buying and holding in your non-registered and cashing out all in one go, it may cause a very large one-time capital gain. It is treated better than inside your RRSP, but depending on what you're holding and what you intend to do with it, the smoothing of your taxable income in your 70s vs having a million in one year and 50000 in the others may also have value if you're going to trigger a capital gain event from a rebalance or something else.

I’d talk to a financial advisor. Having too much in an RRSP can make melting it down from a tax efficiency perspective difficult. You have about 25 years of continued growth. Even if you add nothing more to your RRSP, it will likely double 2 more times before 71 (when you will I assume defer CPP and OAS to). An advisor can model this out for you.

I’ve used HXS and HXT ETFs in non registered accounts to take advantage of the favourable tax treatment of capital gains and to avoid receiving distributions.
You might think of a plan to draw down your RRSP from ages 60 through 70, and deferring your CPP and OAS to age 70 so that you melt down your RRSP on a controlled manner and don’t end up with the tax bomb of forced RRIF withdrawals in your 70s, with OAS clawbacks etc.
The Willems Wealth Planning Group has a bunch of YouTube videos around this topic which you might find helpful and give you an idea of what to expect from a financial planner.

The basic idea of the RRSP is to reduce your lifetime tax bracket by contributing during higher income years (during employment) and withdrawing during lower income years (retirement). As long as this holds true for your situation I would keep contributing. Nothing is for certain regarding whether your current income will be higher than during retirement, but it should be hard to remove your salary when you retire and still be earning more than you do now.
I might think more about an early withdrawal strategy before it converts to RRIF if you retire at say 50 so that you can strategically manage OAS clawback. But I think if you work it out the tax deferral will outweigh the bracket differential over 30 years. The other consideration is whether having in RRSP punishes you if withdrawing at high tax bracket vs non registered account where you could theoretically have capital gains tax deferred also but pay half the tax on withdrawal and no forced withdrawals (though with less flexibility about changing investments and using after tax dollars instead of pre tax dollars). It's a bit complicated and you need to run some numbers for your personal situation with a qualified professional but I suspect you will find it's still pretty good for you to keep plowing money into RRSP at your age.
If you feel like you are headed toward a balance you can't possibly draw down there is always gifting or charity or even trusts for non registered money if you really plan for rrsp to get too large to relieve some of the bracket room from forced withdrawals.
I guess one other consideration would be to your health. If you contribute to your RRSP you are taking some risk that you will live 30 years to gain the full benefit of tax deferral. You might change your strategy a little if you have reduce life expectancy or something like that.

I’m more than 35 years older than you. My RRSP never got even half as high as yours. I had already realized I should stop adding to the challenge of drawing it down. Converting it to a RRIF, I then started drawing it down, while still earning investment gains in it. Every dividend I earn in it gets taxed as employment income, and doesn’t get the tax credit due by virtue of the fact that my dividend is already net of corporate tax paid - which I would get credited for in my after tax investments. Every capital gain gets fully taxed as if it was employment income, forgoing the 50% cap gains allowance. I certainly draw more than the annual minimum, have an employment pension as well as CPP & OAS. And yet I have to work at burning the RRIF down so as to not leave a very large tax bill in the end.

I'm mid-40s, and have about $1.3M in an RRSP. TFSA and RESP are maxed.
I'm wondering if there's a point where I should just stop contributing to the RRSP and contribute to a non-registered account instead. It's going to be tough to burn down that RRSP.
I've read a bunch of wishy-washy discussions online saying things like, "if it's big enough to worry about, just retire", or "stop contributing when the RRIF withdrawls are big enough for OAS clawback".
I'm not ready to retire yet for a few reasons:
1. We still have a mortgage on the cottage (house is paid off)
2. My kid is likely going to post-secondary in 5 years
3. I have a good job that I actually enjoy and it pays well
The thought of retiring while I still have a mortgage and kid to put through school gives me anxiety, so I would probably no consider retirement until after those.
So, I have $1.3M in RRSP, maxed TFSA, maxed RESP, lots of cash in non-registered account, and I'm wondering what to do with future contributions until retirement? RRSP or non-reg?
My wife will have a 6-figure DB pension in retirement in 10 years.
I know, it's a "good problem" to have, but I'd like to better understand if I should stop contributing to my RRSP.

Alternatively, with simple math:
* TFSA: Gross wage × (1 - tax rate now) × Growth
* RRSP: Gross wage × Growth × (1 - tax rate later)
* Non-reg: Gross wage × (1 - tax rate now) × Growth - 50% × Gains × tax rate later
Have growth be whatever multiplier you want. And by tax rate I of course mean Marginal Effective Tax Rate (miss me with that OAS clawback or GIS or well funded pension retort, just bake it in the METR)
As you mentioned, at equal METR (tax rate now = tax rate later) the TFSA will have the same after-tax returns as RRSP by commutativity of multiplication. The best non-reg can ever hope to achieve is approximating a TFSA if tax rate later is 0% (i.e. you realize capital gains strategically to always be below the effective taxable threshold) and you never receive taxable income from your investment from dividends or interest

I'm in a similar situation as you. We're at the point where we are slowing down RRSP contributions. It's still financially better to contribute to an RRSP, but I also want some flexibility. I think I'll need to burn down my RRSP starting at age 60 and delay CPP/OAS to 70... I still won't get OAS.
\- You're already going to be in the full OAS clawback group. It's probably too late for that in a good way. That $1.3M compounded to retirement will be pushing out $300 to $400k a year at 4% by the time you're thinking about OAS.
\- When you're doing the math on the cottage mortgage, keep in mind that you're paying the cottage interest with after tax money. So if you're paying 4%, you need to earn 8% on that money for it to be a wash.
\- When you're doing the math on registered vs. non-registered returns, keep in mind that you'll pay full tax on RRSP withdrawals (so something like 53%) but only half tax on unregistered returns, assuming they're capital gains. RRSP still comes out ahead. By my math, over a 20 year horizon and a 10% average return, you'll end up with 33% more money after tax from an RRSP vs. unregistered.

Read through some comments and a lot of great discussion here, but two things that I think need to be added
1) OAS Clawback is an issue, but you may already have hit a point of no return with that. You may run the numbers to find out that this is not a factor on your next dollar of gains anymore because you're already past the maximum clawback no matter what you do. I have a feeling with 1.3 million and 20 years of compounding, you're almost certainly at this point, but maybe you only have 9 years of compounding and start withdrawing on your kid's graduation day, so it's hard to say with the context here.
2) Churn matters. If you're buying and holding in your non-registered and cashing out all in one go, it may cause a very large one-time capital gain. It is treated better than inside your RRSP, but depending on what you're holding and what you intend to do with it, the smoothing of your taxable income in your 70s vs having a million in one year and 50000 in the others may also have value if you're going to trigger a capital gain event from a rebalance or something else.

I’d talk to a financial advisor. Having too much in an RRSP can make melting it down from a tax efficiency perspective difficult. You have about 25 years of continued growth. Even if you add nothing more to your RRSP, it will likely double 2 more times before 71 (when you will I assume defer CPP and OAS to). An advisor can model this out for you.

I’ve used HXS and HXT ETFs in non registered accounts to take advantage of the favourable tax treatment of capital gains and to avoid receiving distributions.
You might think of a plan to draw down your RRSP from ages 60 through 70, and deferring your CPP and OAS to age 70 so that you melt down your RRSP on a controlled manner and don’t end up with the tax bomb of forced RRIF withdrawals in your 70s, with OAS clawbacks etc.
The Willems Wealth Planning Group has a bunch of YouTube videos around this topic which you might find helpful and give you an idea of what to expect from a financial planner.

The basic idea of the RRSP is to reduce your lifetime tax bracket by contributing during higher income years (during employment) and withdrawing during lower income years (retirement). As long as this holds true for your situation I would keep contributing. Nothing is for certain regarding whether your current income will be higher than during retirement, but it should be hard to remove your salary when you retire and still be earning more than you do now.
I might think more about an early withdrawal strategy before it converts to RRIF if you retire at say 50 so that you can strategically manage OAS clawback. But I think if you work it out the tax deferral will outweigh the bracket differential over 30 years. The other consideration is whether having in RRSP punishes you if withdrawing at high tax bracket vs non registered account where you could theoretically have capital gains tax deferred also but pay half the tax on withdrawal and no forced withdrawals (though with less flexibility about changing investments and using after tax dollars instead of pre tax dollars). It's a bit complicated and you need to run some numbers for your personal situation with a qualified professional but I suspect you will find it's still pretty good for you to keep plowing money into RRSP at your age.
If you feel like you are headed toward a balance you can't possibly draw down there is always gifting or charity or even trusts for non registered money if you really plan for rrsp to get too large to relieve some of the bracket room from forced withdrawals.
I guess one other consideration would be to your health. If you contribute to your RRSP you are taking some risk that you will live 30 years to gain the full benefit of tax deferral. You might change your strategy a little if you have reduce life expectancy or something like that.

I’m more than 35 years older than you. My RRSP never got even half as high as yours. I had already realized I should stop adding to the challenge of drawing it down. Converting it to a RRIF, I then started drawing it down, while still earning investment gains in it. Every dividend I earn in it gets taxed as employment income, and doesn’t get the tax credit due by virtue of the fact that my dividend is already net of corporate tax paid - which I would get credited for in my after tax investments. Every capital gain gets fully taxed as if it was employment income, forgoing the 50% cap gains allowance. I certainly draw more than the annual minimum, have an employment pension as well as CPP & OAS. And yet I have to work at burning the RRIF down so as to not leave a very large tax bill in the end.

I'm mid-40s, and have about $1.3M in an RRSP. TFSA and RESP are maxed.
I'm wondering if there's a point where I should just stop contributing to the RRSP and contribute to a non-registered account instead. It's going to be tough to burn down that RRSP.
I've read a bunch of wishy-washy discussions online saying things like, "if it's big enough to worry about, just retire", or "stop contributing when the RRIF withdrawls are big enough for OAS clawback".
I'm not ready to retire yet for a few reasons:
1. We still have a mortgage on the cottage (house is paid off)
2. My kid is likely going to post-secondary in 5 years
3. I have a good job that I actually enjoy and it pays well
The thought of retiring while I still have a mortgage and kid to put through school gives me anxiety, so I would probably no consider retirement until after those.
So, I have $1.3M in RRSP, maxed TFSA, maxed RESP, lots of cash in non-registered account, and I'm wondering what to do with future contributions until retirement? RRSP or non-reg?
My wife will have a 6-figure DB pension in retirement in 10 years.
I know, it's a "good problem" to have, but I'd like to better understand if I should stop contributing to my RRSP.