Health savings accounts can become remarkably valuable as retirement approaches, which makes one Medicare rule particularly confusing. You may have spent years accumulating HSA money specifically for future healthcare expenses, only to hear that enrolling in Medicare means you’re no longer eligible to contribute. Fortunately, Medicare doesn’t confiscate your account, force you to empty it, or prevent you from using the money you’ve already saved. The major change involves HSA after Medicare enrollment contribution rules, and getting the timing wrong can create an unexpected tax problem. If you’re approaching 65, working past 65, or preparing to retire after delaying Medicare, here is what you need to know about HSAs and Medicare.