[teecee90]

Personally, I usually set myself a time limit.

When I checked my sessions in PO I noticed that my really long sessions were losing sessions....probably because I loose concentration or get frustrated and loosen up too much, play too many marginal hands, try to force the action etc..

EDIT.....dont take this as advice....it works for me, but the best advice is probabaly to play longer at the tables you can beat, shorter at the ones you cant....!!!!