Verified answer

Because of what is sometimes called the 8th wonder of the world, compounding gains.

If you put money away at age 20 you could have 50 years or more before drawing it out. Remember it needs to last through retirement.

There is a number of scenarios you can find on the web.

The simple way to look at it is the longer your money is making money the more money you will have. And that doesn't mean just for retirement. The same holds true for investing outside of retirement plans.

It is better to have your money working for you than to spend your life working for your money.

Good Luck.

Because of the power of compounded interest. The longer the period of time that your savings has to accumulate interest, the more you will have later in life.

For example, $100 invested when you are 30 years old at an annual interest rate of 5% will turn into $551 when you are 65. Had you invested that same $100 when you were 20 years old, it would turn into $899 when you are 65.