When my wife and I go to play blackjack which is a rare occasion anymore; we each sit down with $140 at a 5 or 10 table. We play until 1 of us goes broke, our combined total is double our start, or 3 hours. Whichever happens first we quit. It doesn't mean we are done for the night. Depending on what happened we may play a few slots or get dinner. After about an hour we do it again. We always do 2 sessions. That is just our way of doing things, you will have to figure out what is best for you.
I'm going to have my wife read this, I find it inspirational.
Then forever after I'm gonna say, "It's been an hour, let's do it again. We should always do 2 sessions". Tee hee