Offer your insights or judgment on the input financial query or topic using your financial expertise. Reply as normal question answering

What's the catch with biweekly mortgage payments?
Interest is a fee that you pay in order to use someone else's money. Once you've made the deal, pretty much anything you do that reduces the total interest that you pay does so by reducing the time for which you get to use their money. As an extreme example, consider a thirty-year interest-only loan, with a balloon payment at the end. If you pay it off after fifteen years you pay half as much interest because you had the use of the money for half as long. The same thing happens when you make biweekly payments: you reduce the total interest that you pay by giving up the use of some of the borrowed money sooner. That's not necessarily bad, but it's also not automatically good.