Please Google "Compound Interest". Once you really understand how CI works, you'll have your answer.

From US News, with slight modifications, to whet your interest:

"Obviously, if you just put $1,000 in an account yielding 2 percent and let it sit for years, your money wouldn't grow very fast. The key is to continue adding money to your savings[/investment] account regularly so that you have more money to earn interest. The magic of compound interest is that the more you put in, the faster your money grows.

**Compound interest is also more beneficial the longer you have your money in a savings [/investment] account, so the earlier you start saving, the better off you are. **You can use a compound interest calculator to help you make projections.

If you are 25, and you start with $5,000 in a savings [/investment] account, and you put in $200 a month for 40 years, your money can grow to $158,904.25 by the time you are 65. If you can up your contribution to $500 a month, you can end up with $380,700.34. If you start five years later, at 30, you only end up with $315,965.65. You miss out on tens of thousands of dollars, just by getting a late start."

This one should really blow your hair back:

http://www.businessinsider.com/amazing-power-of-compound-interest-2014-7