The new rules spring from the December 2019 SECURE Act, which attacked long-beloved rules that previously allowed beneficiaries to stretch required distributions over their life expectancies, allowing them to enjoy tax-deferred growth along the way. The new rules apply to those who inherited either a traditional or Roth IRA from someone who died in 2020 or after. Those who inherited IRAs before 2020 still get to use the friendlier old rules. 

The new rules apply when the deceased IRA owner was old enough to be taking RMDs of their own before they died. The new requirements do not apply to spouse beneficiaries, who will still be able to take over the inherited retirement plan assets and have them treated as if they had always been theirs. There's also forgiving flexibility for so-called "eligible designated beneficiaries," such as those who are disabled or chronically ill, minor children of the deceased owner, and others who are not more than 10 years younger than the deceased owner.