Back in the day, I tried to be diligent about balancing my checkbook every month. (This is where you say, “OK, Boomer.”)
I would compare the bank statement with my own record of checks written (many) and deposits made (few) to see if they were the same. Usually, they were not. Usually, the bank said I had less money than I thought I had.
But it was never that big a deal because the difference was usually $1.32 or 86 cents or something like that. Never more than $3. So I took the bank’s word for it — they know how to do math, after all — and set it aside for another month.