The term comes from a paper process. Traditionally, balancing the checkbook was the act of reconciling your personal record of the checks you wrote (your "che

The term comes from a paper process. Traditionally, balancing the checkbook was the act of reconciling your personal record of the checks you wrote (your "check register") against the statement the bank gave you at the end of the month, giving you a chance to correct errors on either side. It is used in a more general context to mean keeping a budget, as someone who would check the bank's work and make sure their own accounting matched to the penny presumably is doing so to ensure he is living within his means.