I never set deadlines. I just work as fast as I can. Likewise when I was poor I never made budgets, but just tried never to spend any money.

I prefer the opposite approach: every time you have a block of time, set a task list of things you want to accomplish in that block, and hold yourself to that.

Problem with deadlines is they tend to back-load a task. If you know you need it done in a week, you might figure it'll take you 3 days to do, and hence start it in 4 days. Of course, things rarely take as long as you expect them to, so you end going over the deadline anyway or stressing yourself out to make it.

With a task list, you'd start that task immediately, and it's done when it's done. If you go over, you have some padding before it's necessary, and you can decide whether to give up on your original task and start the next item, or push through with it and postpone everything else. It's also much less stressful, since things don't get bunched up around the deadlines.