Reply #18: Yes. It isn't a matter of budgeting. It is the surprises.

[Dr Morbius]

Surprise: you blew a tire. Really need to replace both front tires. That's $250, three weeks of groceries.

Surprise: your kid broke her arm. You've found a place where you can get it set for only $500 in cash, and $500 which they'll bill you. Five hundred bucks covers all the bills for a month except the mortgage. It isn't like you have a choice here; find the cash somehow.

Obviously, those who can operate with a little cushion in their checking account do so, but the surprises take that away.