Whenever you have to think about anything, you use precious brain fuel (glucose and oxygen). The brain cannot store fuel, so when you think, make decisions or rely on willpower, you drain your brain.
Think of habits as cars that get 150 miles per gallon. Habits take you very far on very little fuel. Thinking, decision making and relying on willpower are all gas guzzlers. They are like tanks, getting 5 miles per gallon. You can’t get very far driving a tank. Eventually, you’ll run out of fuel and stall.
Self-made millionaires understand this powerful truth. They use good habits to get them far in life without much exertion and this helps them conserve their brain fuel and energy. Because they have good habits, they have more available brain fuel to help them think creatively and make important decisions. The fuel is there when they need it thanks to the habits they formed earlier in their lives.