Good point on IRMAA. Because of the hard thresholds for IRMAA, it might make sense to alternate years of higher income with years of lower income, carefully targeting income levels just under the top of an IRMAA tier rather than every year being in the middle of an IRMAA tier. Going $1 over into the next tier can mean something like an additional $1,000 in Medicare Part B and Part D IRMAA two years down the road. In that scenario, that $1 is effectively subject to a 10,000% marginal tax rate, so it pays to be careful.
