My wife and I have been keeping our finances separate for a long time. Some of my friends just put everything in a big pot. We each have our own pot, but then we have a common pot where we put all the common expenses money, and we pay all expenses from that joint account.

We decide what type of expenses will be paid with the joint account which are:

Food, bills, cars, rent, cellphones

I would like to know what is the most common approach and the best one for married couples' finances.