Lets say you trade the ES and have a 5 point trail stop and a 5 point profit target - those are your goals for each day. Pros: - Prevents you from overtrading once goal is met. - Frees up time to do other things. - Keeps you focused on what you need to do. - Limits losses and protects gains (because by continuing on you can always loss more or give back profits). Cons: - Focus can sometimes turn more on money rather than market action. - If you continue to trade you can always recover losses or add to gains. - You can overtrade. Just trade, trade, trade - opening bell to closing bell.
Basically every trading decisions has its risks and rewards (pros and cons) - ultimately you have to trade in a way your comfortable with. I never used goals up until recently because of all that nonsense talk in most trading literature about not thinking of money and not limiting profit when trading. But that is BS imo.
I use goals as more of a target I'd like to reach, but always measure myself up against the potential I see in the markets. Sometimes the money just aren't there to be made, and then one should both trade lightly (if at all) and not beat oneself up for not reaching trading goals.