My wife and I are both over 59-1/2, under 70, and currently working. We're ready to start taking distributions from our retirement accounts.
She has a Roth, a Traditional whose contributions were deductible, and a Traditional whose contributions were not deductible.
I have a Roth, a SEP, a Solo 401k, and a Traditional whose contributions were not deductible.
Regarding distributions, what sequence, from which accounts, would be best in order to minimize taxation?
That's way too complicated for this forum. You likely need to see a financial planner.
Remember that once social security starts, taking distributions from pre-tax plans will be taxable AND will increase the tax on the social security benefits, so it is advantageous to have some after tax money (Roth IRA or Roth designated 401k or 403b) so your social security benefit won't be taxed. On the other hand, Roth type accounts are not advantageous if you have long term medical needs, because you can be required to drain them before qualifying for Medicaid, where you can't be required to drain a traditional IRA. Pre-tax plans have RMDs once you turn age 72 but Roth plans do not.
Also, for purposes of taxing IRA withdrawals, all traditional IRA account owned by a person are considered one IRA for tax purposes. So when your spouse makes any withdrawal from either the pre-tax or the non-deductible IRA, she will pay tax based on the aggregate total. (In other words, suppose she has $100,000 in a pre-tax IRA and $100,000 in a non-deductible IRA, of which $50,000 is the non-deductible contribution. Since 75% of the aggregate IRA balance is pre-tax, she will pay tax on 75% of any withdrawal, even if she withdraws entirely from the non-deductible IRA only.) Also make sure the accounting is correct on the non-deductible IRAs and you have all your form 8606s from prior tax years, so you can support the non-taxability of a portion of the withdrawal.
@Opus 17 - That's very helpful. Many thanks for answering. Much appreciated.