Q: Please give me one good reason why I, at age 70, should not convert my whole retirement account to a Roth IRA?
A: Currently you do not have to take any withdrawals from your retirement accounts, so right now; you would not pay any addition income tax. At age 70.5 you will have to take your first required minimum distribution form your retirement accounts. Only the amount of withdrawal will be taxed.
If you convert your whole retirement account to a Roth, you will pay ordinary income tax on the full account value. The Federal Government will love you for this choice, to me; this is a good reason not to convert.

disclosures:http://www.hechteffect.net/?page_id=31