You have to earn and invest along with your income. But when you retire, your income will stop. If you don't invest, you can never become rich in a short time. However, if you want to invest, you should have an idea about the investment in advance. You have to have mental willpower. If you are mentally ill, you will not have the desire to invest and therefore you will not be able to become rich. We have to take care of how to keep our health good.