More Good News!
There's still more good news - many employers contribute money to your retirement fund as well. This is called matching funds. It works very simply - for every dollar you put in to your retirement, the company matches a percentage. Let's take a simple example:
Your employer has a 100% match on the first 5% of your salary. So if you earn $1,000 on your next paycheck and are contributing 5%, the company takes $50 out of your pay and puts it into your retirement fund. Then they match that $50, so you have $100 more in your account, but only paid half. You've already doubled your investment!
The matching funds are not yours right away. Some companies have what is called a vesting period. This means if you leave your job before that period is up, you may have to return some of the matching funds. Three to five years is the most common.
However your contributions are ALWAYS 100% vested. It is your money, after all!