Hours spent on computer?

I think I can spend a whole day in front of my computer. Working, resting, working again... but it's not a good idea, actually. If we figure out how to rest effectively, we'll realize that working with a computer considers rest without it. I provided just a single example, but we can find a lot of scientific researches on this matter - therefore, I try to use my computer just for work and on weekends. But when we don't use a computer, we use a smartphone, right  Another problem. It's all about reducing screen time in general.

P. S. Yeah, sometimes I have to work on Saturdays and Sundays, but only if I take days off on Monday and Tuesday, for example.