If you want to ensure that your funds last your entire lifetime, you might choose to purchase an immediate annuity. This could help you to balance your budget, knowing that you will have a certain amount each month to spend, and will ensure that you have at least that much each month for the rest of your life.
If you are concerned that you might pass away soon after purchase, and only receive a small portion of what you paid in, you can choose an annuity that guarantees that your beneficiary will receive the difference of what you paid in to what you had received or one where payments would continue for a minimum of years.