I've been doing this at work for the last 4-5 years, and it's been an incredibly valuable exercise. In my case, it's just a simple spreadsheet called "Things Do

I've been doing this at work for the last 4-5 years, and it's been an incredibly valuable exercise. In my case, it's just a simple spreadsheet called "Things Done". I too have trouble saying "no" when someone asks me to help out, and I decided to keep track of all the things I do that I think add value, but more importantly (along some dimensions), things that the people asking me to help value. I started doing this after I realised that there's lots of stuff that I take for granted, but that other people find incredibly useful because they're simply unfamiliar with the domain or technology in question. I do have the benefit of some relatively trusted senior leadership though, who help me to summarise and focus this list towards the end of the year so that I don't end up emphasising the wrong things as part of my year-end summary.