Also, if you're not usually the procrastination type but find yourself in a procrastination hole: take leave. When you're hungry you eat, when you're thirsty you drink; unusual tendencies to procrastinate are simply another signal that your body is sending you.
It's always good to take time off when you have earned it, you'll come back twice the hard worker than you were before.
I am the procrastination type, but I have lots of friends who aren't, and I've watched too many of them burn themselves out. Some of them are miles smarter than me, and far more hard-working, but my innate laziness and procrastination have actually given me an edge.
I became a bad procrastinator due to overworking myself and almost got a formal verbal warning for it (more of an informal fix your shit warning happened). At the time I had over 1 month [effective] leave "saved" up; I took it.
I came back and became the exact opposite - by a very substantial degree. It felt like I was 20 again: I had all the brains, guts and dedication that got me hired in the first place.
Burn out can really mess you up - far worse than being a plain-old incompetent bad hire.
The danger is that you come back and find you haven't found the "twice the hard worker" energy that you had hoped, at which point the "take leave" solution stops seeming like a realistic option. I do think taking leave, as you suggest – or even just working on something different for awhile – usually works wonders, but it only makes the hole feel deeper if it doesn't.
You always can - even if it means time between jobs. If your employer won't let you they are doing both themselves and you a disservice and you'd be best be far away from a leader that unwise.
Do floor managers in factories let their machines go to rack and ruin? No, they maintain them and leave is how you perform maintenance on humans.
"Do floor managers in factories let their machines go to rack and ruin?" From my experience developing software for and supporting users of machine tools, ...yes.
Most organizations designed by and made of humans are inefficient and ineffective.
If you always bail on (quit for managers, fire for subordinates) people who are fuck ups I feel like you'd have a hard time staying fed / keeping the lights on -- but maybe I'm just unlucky in my professional experience so far.
It's always good to take time off when you have earned it, you'll come back twice the hard worker than you were before.