How do you handle joint expenses like rent/mortgage and all the kid stuff?

We split them up, roughly based on ability to pay. It reduces friction, but the downside is that I think it reduces our ability to optimize expenditures. (You don’t have two person sign off on most expenses.)

My wife and I basically do this with a joint checking account + credit card that we contribute to (somewhat unequally) every month an amount that is designed to cover 1 month's of expenses plus a little buffer.

I find it makes it a lot easier to know that $X thousand/month is my "family expense" and then everything for that is easily accounted for in a way that is totally separate from my personal finances.

I actually have two separate mint accounts, one for family expenses and one for my personal stuff.

That makes a lot of sense. We’ve been trying to set that up just for simplicity of keeping track of auto payments and whatnot, but it’s so hard to switch everything over.