I only do them when there is a big gap between finding out about the task and doing it. Mostly I do them on the end of the day friday so when I get back on Monday and have completely forgot what I was working on, I can see a few checklist items for what I was in the middle of.

Creating a 20 point check list is just pointless. Unless maybe it's a list of things you need to verify before pushing something forward and you absolutely can not forget any of them.