i do something similar to poker_pup.

i will play short sessions of 10-15 minutes sometimes. btw, i don't do it because it is fun - i do it because i have spare time and i think i will can make a quick profit in that time.

i will usually play 40mins to 1hr long sessions. but i haven't had too much free time recently.

i will move tables quite a lot. i don't want players picking up reads on me. i feel that i am more profitable when moving from table to table. if i play 1hr or more with the same group of players i feel that they start to play much better than me and work out what i'm up to. if i hit and run every hour it's hard for players to get great reads.