I've been doing this recently, and it's really helped a lot.
If I think of something I need to do, I can jot it down real quick and put it on the list in order of importance to get it done.
I've been using the note app on my phone, which makes it easy to insert items into an already created list and it's easy to add new items.
I've found I get done a lot more things that I actually want and need to get done this way!