Paying off a mortgage is a long-term commitment—30 years in most cases, and costing hundreds of thousands in interest. But if your goal is early retirement with a paid-off mortgage, you can meet that goal—and save many thousands in interest along the way—by paying down the principal with a few extra bucks here and there.

The caveat, said Moneycrash.com financial advisor David Bakke, is that you specify on these extra payment checks to your lender that the funds are to be used for principal deduction only.

Bakke offers four ideas for paying down your mortgage early while hardly feeling the pinch:

• Lower the interest rate – Stay alert to opportunities to lower your mortgage rate. Dropping 1.5 to 2 percent interest from a 30-year fixed rate mortgage can lower your payment by several hundred dollars per month. That’s money you can put toward retirement savings, vacations, or kids’ college accounts – or toward paying down your mortgage even faster.
• Turn a small luxury into an extra payment habit – Consider the small, perhaps daily luxuries you are willing to forego; the $4 latte every morning…a magazine subscription you don’t need. Stash that money and use it toward principal reduction.
• Turn underperforming investments into equity - Many people have investments that are returning less, as a percentage, than their home mortgage interest rate is costing them. If that's the case, and you have no reason to think that the investment will turn around soon, it might pay to put that money toward paying down the principal on your mortgage.
• Stash those regular or unexpected little windfalls – Got an unexpected tax refund? A larger-than-expected birthday check? Or perhaps you save a few bucks on groceries each week by using those clipped coupons? Stash the money you saved, or any other extra amount, and apply it each month to mortgage principal.