Yes, I tend to write as free-form notes. I don't bother adding a checkbox. It's not really a major problem. Usually what happens is I notice a note which was implemented and then I may start checking other, lower-priority items; sometimes I notice others which are also done and I also clear those.

I guess, I don't really need a TODO list; what I care more about are details; I want to capture my nuanced reasoning about a problem in case I don't address it for a while; to save myself from making a bad decision in the future (when the relevant info won't be so fresh in my mind).

I like to scope out a problem and identify some possible solutions as soon as I encounter it; the optimal time. I find it helps to decouple the work of 1. Understanding the problem. 2. Coming up with possible solutions; and 3. Choosing a solution and implementing.