https://invested.mdm.ca/should-you-contribute-to-a-spousal-rrsp/#:~:text=The%20main%20advantage%20of%20a,than%20one%20income%20of%20%24100%2C000.
When a spousal RRSP works: 4 scenarios
Here are some situations where a spousal RRSP might be a good idea.
1. Buying your first home
Shazia and her partner, Jeff, are ready to buy their first home. They are looking to take advantage of the Home Buyers’ Plan (HBP), which allows a new home buyer to withdraw up to $35,000 from their RRSP with no penalties.
As the higher income earner, Shazia has been contributing to her own RRSP and to a spousal RRSP for Jeff. This means that Shazia can withdraw $35,000 from her RRSP, and Jeff can also withdraw $35,000 from the spousal RRSP (even if it’s less than three years since the last contribution)..
The couple will have to put this money back into their RRSPs over the next 15 years. (To count as an HBP repayment, Jeff must contribute to his own RRSP, not the spousal RRSP. Shazia cannot contribute to the spousal RRSP and consider it a repayment of Jeff’s HBP withdrawal.) If they don’t make the repayments, there is a tax penalty: 1/15 of the withdrawn amounts would be treated as their income each year, on which they would need to pay tax.
2. Planning to have children
Iris and Zander are a recently married couple who would like to have a child in the next five years. Iris plans to take extended parental leave from her job after having a child and use her spousal RRSP as additional funding.
As the higher income earner, Zander can contribute to the spousal RRSP now and benefit from a tax break of up to 50% of the contribution. When the couple has a child, Iris can then withdraw the funds at a much lower tax rate (assuming the three-year attribution rule isn’t an issue). Note, however, there is a withholding tax when you withdraw.
https://www.canadalife.com/investing-saving/saving/registered-retirement-savings-plan-rrsp/spousal-rrsp.html