The age at which you have to start pulling money out of retirement accounts has changed three times in recent years.
It was 70 and a half for decades. Then 72. Then 73. It is scheduled to become 75.
Which means most of the advice in circulation is wrong for somebody, the number in your head is probably the one that applied when you first learned about this, and a meaningful number of people have taken distributions years earlier than required because nobody told them the rule moved.
Here is the current version, including the deadline that produces the single most expensive first year mistake in retirement.