Rule number 1 (Multiple Income)  

let's say you have planted 100 apple trees to sell the fruits in Market-In the beginning when you're apple plant is small. It will be very difficult to keep them safe. There will be many problems will pop up. But once they grow big they will need less maintains.

Similar  to these, you can also create multiple income. Which need maintains in the beginning and once they are full grown. You don't need must maintains anymore.