It varies for me, When I have nothing to do I'll just stay on it while I listen to music, or watch videos in the top right hand corner of my screen for like 8 hours, If I have plans maybe only 1-2
Usually I'm multitasking and on it from when I get home, to when I go to bed, then not to mention at school during 1st, 2nd, and 4th periods lol Which, Thats 80 minutes each period lol I think Im on here too much