I mention this Tip on my Book 25 Tips for Productivity. The idea is simple, begin a list on witch you will write down all those things you will stop doing, because it is more efficient to hire someone, or because you shouldn’t be the one doing them.
i.e. I don’t wash my car, it is item #1 on my Do Not Do List. Wash the car put me in a faulty mood, therefore, I pay happily.