Required Minimum Distributions are the age at which the IRS stops letting your retirement savings grow tax-deferred forever and requires you to start withdrawing — and taxing — a portion of it each year. Exactly when that starts depends on your birth year, thanks to a phased-in age increase from the SECURE 2.0 Act. * If you were born between 1951 and 1959, your RMDs begin in the year you turn 73. If you were born in 1960 or later, that age moves up to 75. Anyone already past their RMD age before these rules changed continues on their existing schedule. * There's a one-time timing quirk in your very first RMD year: you technically have until April 1 of the following year to take that first withdrawal, instead of the usual December 31 deadline. Delaying to that later date means you'll end up taking two RMDs in the same calendar year — your delayed first one plus your normal second one — which can push you into a higher tax bracket for that year if you're not careful. * The rules apply to Traditional IRAs, SEP and SIMPLE IRAs, and most employer plans like 401(k)s and 403(b)s. Roth IRAs are exempt entirely — you're never required to withdraw from one while you're alive. Miss an RMD or take less than required, and the penalty is steep: a 25% excise tax on the shortfall, though it drops to 10% if you correct the mistake within two years.