[Rain Man]

Occasionally I'll hear some truth that boggles my mind in its non-obvious brilliance, and I heard something about retirement savings the other day that I have to share.

One of the obstacles to retirement savings is the amount that's needed. If you don't have a high income, or if you start saving later, it can be easy to see the task as insurmountable.

But what I heard was something I'd never thought of before.

If you're behind on your savings, consider this as a motivator. It's really tempting to take early social security, or even full-age social security (at age 67 for most of us). But there's a huge benefit to waiting until you're 70 to take social security. If you take it at 70 instead of 62, the amount will be roughly 75 percent more for the rest of your life.

So if you're behind on retirement savings or you can't save much, target being able to support yourself until age 70 without social security. Then when you take it you'll get a lot more money to support yourself later, with no extra cost. It represents a huge ROI on the savings you can build, and leverages your money to a massive extent.