"Individuals and their planners need to run the numbers to determine if a total or partial conversion works for them," he says.
You may need help anyway determining how much of your converted savings are taxable, particularly if you have deductible and nondeductible money in your IRA.
For those willing to go it alone, the IRS provides a work sheet to help calculate the taxable part of an IRA in Publication 590.
Will it pay?
Generally, converting to a Roth IRA makes sense for those who expect their federal tax rate to remain the same or go up after retirement, since their earnings would not be subject to tax upon withdrawal.
Younger employees are also more likely to benefit because they have a longer time horizon to make up for the immediate tax hit and more years to benefit from compounded growth.
Older individuals, however, who are financially well-positioned and approaching age 70 1/2, when required minimum distributions begin for their regular IRA, may also do well by converting part of their savings to a Roth.
Such a strategy helps lower the value of their regular IRA and as a result, reduces their required minimum distributions. In addition, access to tax-free money affords retirees flexibility when it comes to taking retirement plan distributions.
It also, of course, gives their earnings a chance to grow tax-free for as long as they like.
Finally, those focused on estate planning are good candidates for a Roth conversion as well, says Kaster.
"If the IRA owner's main priority is to provide for heirs at death, then conversion to a Roth makes sense," he says. "Because no minimum distributions are required from a Roth (unlike with a traditional IRA), a Roth is superior to a traditional IRA as a vehicle to pass on wealth, since the assets can sit in the account and accumulate."
Need money soon?
If you think you might need to withdraw from your Roth within five years of your conversion, however, you should plan to leave your money in a traditional IRA.
Distributions of earnings made from a Roth that is less than 5 years old are subject to the 10 percent early withdrawal penalty.
Consult your tax adviser to determine whether a Roth rollover is right for you.