It depends in my case. Depends on how the game is played and how well it works in my favour. I try to stick to rush/fast poker mostly and it varies between 1-2 hours for bad sessions when I feel I'm not up for it and make several bad decisions in that amount of time. On good days, I spend 10-12 hours with breaks in between and also avoid playing deep stacked. If I feel I'm too tired or not concentrated enough or if I start making several bad decisions in a short amount of time, I simply close it and move on to do other things. I come back to it a day or two later when I analyse what I've done wrong and what I should have done instead and then go back to try and correct my mistakes and play well. It's just my way of improving my play and not losing much. And it works, for me. I have had quite lengthy breaks this year because I was not in an adequate mental state to win and I knew that if I did play, I'd lose. Overall, I have only grown my several bankrolls across multiple poker clients and never bankrupted one. I wish I could play without having to eat, sleep, do other necessary things etc. but I'm not a robot yet.