The key point is that "If your Medicare Part A coverage overlaps when you made contributions, you’ll have to pay a tax penalty."
"if you decide to delay enrolling in Medicare part B, make sure to stop contributing to your HSA at least six months before you do plan to enroll. This is because when you enroll in Medicare Part A, you receive up to six months of retroactive coverage, not going back farther than your initial month of eligibility. If you do not stop HSA contributions at least six months before Medicare enrollment, you may incur a tax penalty."
我的理解：如果某人今年7月65周岁，那HSA 放到6月止应该可以。不过这个tax penalty一次性的，差2，3 个月应该也罚不了多少。当然最好不踩坑。
