The "long periods of time" part got my attention... Usually the most difficult part is to get started, but just questions seems to suggest that is not hard for

The "long periods of time" part got my attention... Usually the most difficult part is to get started, but just questions seems to suggest that is not hard for you to get started, rather than keep going. Do you like the thing you are supposed to focus on? Because IMO, there is no substitute for sustainable focus if you don't like something (or you aren't forced).