An additonal topic you may consider around this question is the use of a QLAC or Qualified Longevity Annuity Contract. QLAC's are relatively new in the marketplace and have some definite advantages for investors.
When you retire, the IRS takes your IRA value and tells you what percentage to withdraw every year in order to avoid paying a penalty tax on under withdrawals. Following their tables, you will eventually use up your entire account. The IRS bases their Required Minimum Distribution (RMD) based on your account value as of December 31 of the previous year.
A QLAC is issued by an insurance compnay. You can invest 25% of your IRA up to, currently, $125,000 in such a contract. With that purchase, the insurance company promises to pay you a fixed amount for as long as you live, even after they have paid you all of your initial investment. You can't run out of money. In addition, when the IRS looks at your IRA balance each year to determine your RMD, the value of the QLAC is not included in the account valuation, thus lowering your RMD despite the fact you have an income coming from the insurer.
If you have an interest in QLAC's after this brief description, do a Google search on QLAC's. There is a lot of good information available regarding these contracts.