How do you manage your household budget? Do you split expenses?

Managing a household budget is an important aspect of family financial management. There are many ways to do it, and the choice of method depends on the preferences and needs of a given family. Some people divide expenses among household members, others write down projected monthly costs and allocate money into so-called piles. There are people who do not keep a budget and still manage well. How about you? Do you keep a household budget? If so, how do you do it? Do you divide expenses when you are married/in a relationship?