Actually I have used several, but I find writing down a "task list" helps me keep on track. Otherwise I get distracted and get 100 projects going at once. Plus it helps to make sure I get sequential things in the proper order. In a couple cases I have had to get something done for a an operating weekend, I have found that a list helped make sure I got everything done and was ready to go.
I also like checklists to prepare for an op session to make sure I don't forget anything (shoulda bought sodas, rats) and to go over my pre session orientation. I find that having a set list actually shortens the talk, less chance to get off track.