I really love to play poker and the reason for that is the adrenaline in your body while playing in the action of the tables. The main reason everyone should play is for fun. The main target should not be the money. Yes, it is very exciting when you win and get money, but you should recognise that poker is not only money. You have to know your limit and when you see you are not happy and you are starting to lose, that means you should stop, go to do something else and play again on the next day when something else will be in your mind. That is the way I follow since 2012.
About how many tournaments one player should play - it depends on the person. I can play whole day, if that makes me feel good, especially if there are some prizes listed into my bank account. If you feel good you can play all day.