Currently (living together, not married) - we both have individual accounts, as well as a joint account and joint card. The joint account is contributed to pro-rata according to our salaries, and our joint expenditures come out of that. We live in his condo, so I don't contribute to the principal of the mortgage, but everything else, we take from the joint account.
We are going to close on a piece of land together in September. At that point, we've decided that we will change to a one-pot deal for simplicity's sake. We'll be writing up a pre-cohabitation agreement, that will stipulate that if we split BEFORE having children, we each leave with whatever assets we brought into the deal.
Once we have children, we keep the one pot deal, naturally. If we break-up AFTER children, we will split everything 50-50 in order to keep things as comfortable and "even" for the children no matter with whom they're living.
Of course, these are situations that have not occurred yet, but it's how we've decided to organize things in advance.
As a note, we've been together 6+ years, we aren't married, nor are we likely to get married (although you never know). In Canada, as a poster above explained, retirement accounts are individual. However, once we mutate to a one-pot deal, we'll contribute into our retirement accounts from that one-pot. So theoretically, although each account is in an individual's name, the money going in is shared money. Our salaries are currently approximately 40% me, 60% him. That's not likely to change much, although the split might skew higher for him. However, I have considerably more assets to my name. So in the short term, I have more to lose, in the long term, he would have more. With our agreement, we both feel comfortable that no matter what happens, we're both protected and/or protecting the well-being of any eventual children.