Estimated Tax payments are recommended anytime your withholding is insufficient. The IRS defaults to taking your current year tax liability and allocating it evenly across the months. But if you income is not regular, (e.g capital gains and IRA distributions are likely non-regular income) then estimated payments are like needed to avoid penalties. But my main here point is that the estimated payment are not due exactly on calendar quarters as you might expect. At least as of 2022 tax year, they are due 3/31, then 5/31, then 8/31 and lastly by 1/15 of the subsequent year. Precise records of when you received income (by category of ST < Cap Gains and Divs) by these dates is required to fight via a 2210 form.
