My IRMAA link in Retirement thread from October just showed as “popular” (50 views). So I’ll repeat it here.
Most retirees don’t have enough earnings to worry much about IRMAA, a sort of medicare extra “tax”. But folks considering Roth rollover (converting taxable 401K to a non taxable Roth, ie eat the tax pain now), sale of appreciated assets etc need to be aware.
NOTE: If all of your taxable income years will be under $194K (joint) or $97k (single), IRMAA is not a concern. Also not a concern if those years happen before you are about age 63 (IRMAA based on 2 year prior tax forms), since Medicare starts at age 65.