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.

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It seems that this boils down to preference, believe, fairness and age within the couple.  I think all answers have been great.  I think we are taking the approach that we both feel comfortable, but we don't have kids now, and we don't know if we both will be working once we do.  I am trying to say that our way might change depending on our future self. 

To answer the latest comment below.  The only problem we have encountered is that I am more a saver and she is more a spender, so when we want to do things that we need to put more money from our pots, usually she will not have enough.  We have minimized this by opening savings account for her, but we are still learning through the process. 

Again thanks all for all your good responses.