Setting goals for sessions is a terrible idea in my opinion. If you set a goal like that for yourself, then hit it early, you might convince yourself to leave a game that is very good. Or, you might find yourself down for the session and close to the time limit that you set, so you take chances that you might not otherwise take in order to get yourself even or to your goal. Setting goals for yourself over a long period is good for over a long period, where you can evaluate your play over the period and see what you have achieved. But over a term as short as 1 session anything can happen, and setting goals such as "I have to make $100 today" can harm you over a longer term, and as poker players we have to look at the long term, lest variance eat us alive.