I keep a hledger timedot file[1] open in a hot-key drop-down iTerm window. Each 15-minute chunk is logged with a dot. I group dots into hours for quick visual scanning.
2019-01-08
fos.hledger.sup .
adm.email ..
adm.finance .... .... ..
fos.plaintextaccounting .
fos.hledger.issues.941 .... .
has-res ...
biz-res ..
I've trained myself to update this often while at the computer, and before walking away. Delayed retroactive logging is also pretty easy. Working in quarter/half/whole hour chunks, and in rhythm with the clock, and having a pane showing recent sleep/wake/timelog-saved events, all help. Not every day is the same; this system has been quick and flexible enough to suit a range of conditions. I can set daily/weekly/monthly time budgets if I want. Some more details at [2].
[1] http://hledger.org/timedot.html
[2] http://hledger.org/Time-planning.html#simons-hledger-time-da...