Generally speaking, ignoring considerations about leaving tax-deferred retirement accounts to beneficiaries, you'll want to make taxable distributions from retirement accounts so as to spread the taxable income out somewhat evenly over your life expectancies so as to minimize the amount of this income that falls into higher tax brackets. For amounts beyond that which you need to spend, that can be done by doing Roth conversions as Opus 17 suggests. A common approach is to do Roth conversions so as to fill out your current tax bracket. Also as Opus 17 indicates, though, the tax brackets are scheduled to increase back to their former levels in 2026, so you may want to convert more than what would fill up your current tax bracket up through 2025. However, keep in mind that if you are enrolled in Medicare Part B or D, Medicare IRMAA is based on your AGI so you'll want to factor in any IRMAA increase as if it was an increase in your tax rate. A good tax planner should bring up all of these points.
For others who might read this thread, deferring taxes is not necessarily bad, but it's not uncommon that one's marginal tax rate in retirement will not be substantially lower than when one is working. This is particularly true when an individual first starts to work, when taxable income is lower and the deferral is less beneficial, and would likely benefit more from Roth contributions instead of traditional tax-deferred retirement contributions. Planning how and when to take requirement distributions should probably start much earlier than age 68 or 70. Age 50 to 55 would be a reasonable time to start. This gives a much longer timeframe over which to realize the taxable income, providing the opportunity to reduce the amount realized in any given year to avoid the income falling into higher tax brackets.
