This is something that I've grappled with in the past for encouraging myself to do something or finishing a task, but I've failed to find something effective or encouraging. I think the main reason is that if I can do something for myself then I can do it regardless of getting my task/work done; therefore, it loses its value. I understand that this takes quite a bit of discipline as well.
Has anyone come up with an effective solution to this problem?
There have been studies. Intrinsic motivation is always better. That said, if intrinsic is missing, for extrinsic, they say rewards should come often and timely. Eg, giving $100 for passing a midterm is not as effective as $10 for passing the weekly quiz.
To help myself accomplish tasks I’m not interested in, I leverage the rule of threes. I set 1-3 accomplishable tasks for a time period (say before lunch). Instead of “rebuild a deck,” I have much more fine grained milestones: tear out the old deck, take old debris to landfill, level the ground, place footings... The reward is moving onto the next task. By limiting how many projects I have, I don’t get to start a new one until I get something else “done enough.”
Some examples I’ve heard from others where external rewards helped: someone would buy the next $item in $set (game pieces for a table top game, or car part for a restore, or anything that let them do more with a hobby), would add $funds to $project (dollar in the music instrument fund, n minutes of video games, time to decompress), and my favorite, they would do something nice for someone (write a quick love note, or let someone know you appreciate them and why, a small compliment; give themselves the joy of helping others).