Even though your wife can’t contribute to an HSA after she signs up for Medicare, she can still use the money tax-free for medical expenses that aren’t covered by insurance -- such as co-payments, deductibles, prescription drugs (including over-the-counter drugs with a prescription), vision and dental care, and a portion of long-term-care premiums based on age ($3,290 for age 61 to 70, for example). She can also use the money from the account tax-free to pay her premiums for Medicare Part B, D or Medicare Advantage (just not medigap premiums). For a list of eligible medical expenses, see
IRS Publication 502.