The earlier you start saving, the less you'll need to set aside every year to meet your goals. That's because you allow your money more time to grow -- the gains on your invested savings will build on the prior year's gains. That's the power of compounding, and it's the best way to accumulate wealth.
Saving at least 10% of your annual salary for retirement is recommended, but the older you start saving, the more you'll need to save. If you start at 50, you may need to put away 30% a year and still postpone retirement by a few years.