Finish a task, start the next one, forget the first.
On a full day of project work, one task leads straight into the next. That's good for getting things done. It's bad for remembering, a few weeks later, what the day actually went to.
Month-end billing meant piecing the month back together:
- Digging through emails to see which client asked for what, and when
- Reading through check-in history to see what work was saved and on which day
- Guessing how long each piece of work had taken
The research took hours of its own, so invoices went out late. Sometimes a small job never got billed at all, because working out the time would have taken longer than the job itself. And on fixed-price projects, there was no reliable record of how long the work had really taken.