You empty the tank when you sprint. But you also only sprint to exhaustion for 10-20 seconds max. When the sprint is a five or six-day block of time, you must pace yourself.
This is one of the most valuable reasons for tracking your time and perceived effort day after day. You can see yourself start the week and have incredible Monday-Wednesday efforts, but then it slips on Thursday, gets worse on Friday, and by Saturday it’s all over for your productivity.
If you contain yourself on those first three days and slow down–especially when you think you don’t need to–you will have the mental and physical reserves in the tank for later in your sprint.
Track your work and pace yourself. It’s worth it.