1. Almost everything in life - friendships, jobs, hobbies, etc. - costs money, time, physical energy, and/or emotional energy and rewards you with one or more of the same.
2. For example, a job costs you time and physical/emotional energy, but rewards you with money. Creating art costs you money and time, but rewards you with emotional energy. Friendships costs time and reward with emotional energy.
3. Sometimes, things costs you the same thing as they reward you with - working out costs you time and physical energy, but rewards you with both as well.
4. When you are looking at your life and trying to organize what and who are important, look at the ledger. For example, bad relationships costs time and emotional energy and reward you with nothing. A bad job costs more in time and energy than it pays in money.
5. Keep the ledger in your head and cut out those things that drain your core resources - time, money, and physical/emotional energy - but that provide nothing in return. Make those things and relationships that add more to the ledger than they costs your priorities.