Money Mistake #3: You Forgot What Pampering Yourself Really Means

Think back to the first time you experienced a favorite splurge—try to recall something that so lit up the pleasure centers of your brain it is still seared in your memory. Now think about the last time you spent money on the same thing. Not so memorable? It's called "hedonic adaptation," and it's why, no matter what we have, we always want more. Expensive coffee every morning isn't a treat; it's a habit.

Solution: Step one: I know you've heard this before, but you need to create a budget. By putting your priorities down on paper, and funding the top priorities first, you can prevent yourself from paying for your barista's retirement instead of your own.

Step two: Reward good behavior. One of the reasons it's so hard to be a disciplined saver is that it's much easier to imagine the pleasure you'll get from that Frappuccino today than to picture what that $4 will be worth 20 or 30 or 40 years from now. Besides, what will you spend it on then anyway? Will caffeine still be legal? Reward yourself for virtuous saving behavior by splurging with 5 or 10 percent of money set aside for savings. But spend it only on something you don't buy all the time. You'll associate the reward with the saving, increasing the odds you'll continue to be disciplined.

Money Mistake #4: You Started to Pay Extra on Your Mortgage to Pay Off Your House Early

Paying off your house early sounds like a financially smart move. And it's hard to put a price on peace of mind. But a study by two University of Texas professors and a Federal Reserve banker found that diverting that money instead to a 401(k) was a better move. It's a long academic study, but the key is this: You pay off your mortgage with after-tax dollars, which means that for every $1 you make, only 70 cents or so goes to the bank.

Solution: Contribute pre-tax dollars to your 401(k), so the full buck goes in. Make that $1.50 if you get a company match. As that money compounds over the years, you come out far ahead.

Next: Paying too much in fees