Spousal RRSPs are ideal for couples with unbalanced incomes. They can save couples a lot of money, although they are less important than they used to be. The idea is to equalize the incomes of the spouses as much as possible to reduce your tax bill. It works because you pay far more tax on a single $100,000 income than you do on two $50,000 incomes.
The best way to use them is for the higher earning spouse to contribute to a spousal RRSP in his or her partner’s name. These contributions will use up some of that person’s contribution room, but when the RRSPs are wound up, you’ll have two smaller incomes instead of one big income, saving you big on taxes.