It's worth making the effort to document your time because you will most likely underestimate otherwise. You are used to thinking of it as something you do for fun, and the time goes quickly when you're not looking. When I was in a guild we were also required to keep track of our time because to be designated as a charitable organization they have to be able to document what the contributions are. If you don't report accurately, you are giving the group less credit than they deserve. It was a difficult habit to form, but keep a note paper taped over the power switch and a pen next to your machine and write down the time when you power up and power off. Put another notepad by the cutting table - you can consolidate the notes later. Time spent shopping you might be able to track by looking at the time on your receipt, if you know when you got to the store. Cutting and so on are all a valuable part of your donation and deserve to be noted. If you use a smartphone, you can keep notes on it, and use the stopwatch function so that you can pause it while you answer the phone or have lunch or whatever. Or set the countdown timer to 1 hour, jot down a tick mark when it goes off and start it over after you take a bit of a break.