The freelancer's bookkeeping problem isn't maths
It's timing. The receipt arrives while you're mid-project, the client pays while you're on another call, and the plan is always to "do the books on the weekend." The weekend never comes, and the quarter ends in a shoebox of paper and a guilty scramble.
The fix isn't discipline — it's shrinking the task until it fits in the gaps you already have. Thirty seconds when the receipt is still in your hand beats three hours of reconstruction three months later.