People must take their first RMD in the year they turn 73, except the first one can be postponed until the early part of the following year.
So people born in 1952 take the first RMD in 2025. It can be postponed until April 1 of the 2026, but if you postpone it until 2026 you still have to also take the 2026 RMD during that year.
Participants in a work-place retirement plan (401K, profit sharing) can delay the RMD until they retire unless they are a 5% owner of the business sponsoring the plan.
For an IRA inherited after 2019 usually you must have it distributed within 10 years.
More details, including exceptions for surviving spouses or minor children who inherit retirement plans. If his document still refers to tax year 2024, add 1 to the dates for tax year 2025.
Eventually the age for starting RMDs will be 75, but not until 2033, so we don't have to think about it for awhile.