system
Given the following post, respond as if you're commenting on Reddit:
human
How do you decide when to call it a day? And how many hours a day do you spend doing "real" work?

I've tried leaving school/ the library at a set time, but I could never get what I want to get done done. 

I've tried only finishing the day when I've finished what I intended to/need to get done, but I end up losing sleep and getting a bit burned out.

And no, I am not aiming too high or being too hard on myself. I track the time I do "real" work and it's usually not that much. Also I basically can't get any work done if I'm not at school or at a library, even coffee shops won't do (which might be a positive in some way) so now I feel bad every day about not getting things done and yet I still stay up really late doing non-work and end up getting up late and starting the day late and just don't know how to break this vicious cycle.

I know I should probably build some routine into my life but I'm simply not tired enough to fall asleep at maybe even 2 am, and if I make myself get up really early then my brain just won't function for the day and I end up drinking too much coffee just to get some reading/writing done and then can't sleep due to the coffee. Tried working out in the evenings and at night, didn't help much.

Help?
gpt
A good friend would say that if he did 4 hours of pure productive work a day, excluding everything else, from coffee breaks to bureaucratic meetings to surfing the net, day in and day out, he’s happy and as productive as he could be long term.