Reducing the value of your traditional IRA to reduce future RMDs will reduce your AGI in future years, possibly reducing the marginal tax rate on those future distributions. If you are considering taking distributions now, there is no reason to convert the money to a Roth IRA rather than put the money from those distributions in a non-retirement account. Roth IRAs have no RMD requirements and will continue to grow tax free (distributions of earnings will be tax-free 5 years after the first year for which you make a Roth IRA contribution). In addition, your beneficiaries will continue to be able to stretch distributions over their expected lifetime, allowing the investments in the traditional Roth IRA to continue to grow tax free. The common suggestion is to convert to Roth an amount each year that just tops out your current tax bracket, particularly if your tax bracket will be the same or higher when you must begin taking RMDs from your tax-deferred retirement accounts.
Be aware that if 85% of your husband's Social Security income is not already being taxed, the increase in income from the IRA distributions can push more of his social Security income to be taxable, multiplying your tax bracket by as much as 85% in determining your marginal tax rate. You'll need to factor this into your decision whether or not to take distributions from your traditional IRAs now. You might also consider taking IRA distributions before age 70½ to use for expenses and delaying beginning your Social Security until age 70½. Modeling the possibilities can be a mind boggling exercise; it can be helpful to use the CD/download version of TurboTax rather than the online version so that you can try different scenarios.
