Time tracking best practices

Some (if not most) advice is pretty self-evident. But number 15 is interesting, about the legal profession and how lawyers round time when billing clients:

Rounding is a common practice in the legal profession and is the reason why lawyers can end up earning more than they actually work. Because they bill by 1/10th hour, a 30-second phone call and a 2-minute email are both rounded to 6 minutes for total of 12 minutes. This way, they can easily bill 8 hours in 6 hours (while staying perfectly honest).