IRA distribution rules say you must begin receiving distributions from your IRA by April 1 of the year following the year you reach age 72. Rules apply to 401k plans if you are retired.
If you will reach age 72 in 2021, you will be required to receive your initial distribution by April 1, 2022. And you will be required to receive your second RMD by Dec. 31, 2022. If you do not take your first distribution in 2021, you will end up with two distributions for 2022. Can you say a higher tax bracket perhaps?
HOWEVER, also keep in mind that the new IRS required withdrawal tables go into effect 1-1-22. At age 72 they are 6.65% lower than the current tables. That means you are required to withdraw less from your IRA and the difference between old and new tables grows each year you are older.