They say there are only two certainties in life: death and taxes. But that doesn’t mean we have any control over the actual timing of our death, which makes retirement planning hard.

Projecting your life expectancy is a critical part of executing a retirement plan as it determines how much you need in your nest egg and your drawdown tactics.

According to the Social Security Administration, a 65-year-old male has an average life expectancy of 19 more birthdays to reach 84. Women can expect to live a little longer: A female turning age 65 today can expect to live, on average, until age 86. In fact, 1 out of 4 65-year-olds will live past age 90, and 1 out of 10 will live past age 95.

Living longer is good news, but it increases the risk of outliving your retirement savings if you don’t plan accordingly.

Retirement income certified professional and Director at the American College, David Littell, offers the following tips to help boomers plan for longevity risks in retirement:

Boomer: What are some solutions to longevity risks for baby boomers?

Littell: The most direct solution for longevity risk is to increase income sources that are payable for life. This can be accomplished in a number of ways. The best place to start is to defer Social Security benefits to increase lifetime payments. Social Security has an added advantage in that benefits increase for inflation each year as well. Another option is to choose a life annuity payout option—instead of a lump sum—from an employer- sponsored retirement plan.

In addition, there are a number of commercial annuity products that can provide lifetime income. A life annuity can create a stream of income over a single life or over the joint lives of a couple. Annuities can be purchased that provide an income stream starting immediately – or, with a deferred income annuity, income can be purchased prior to retirement. A deferred income annuity can be purchased to limit longevity risk in one’s later years. For example, buying an annuity at age 60 that begins at age 80 can be a cost effective way to limit longevity risk. Deferred annuities can also be used to create income for life as these can be annuitized at a later date, allowing the owner to lock in lifetime income. Deferred annuities can be purchased with riders that provide for a lifetime withdrawal at a rate specified in the contract. Be sure to read all the disclosure before investing in annuity to make sure you understand all the potential risks, fees and terms.

Boomer: How important is it to make a good estimate of life expectancy for planning for longevity risk, and how can we create our own estimate?

Littell: Unless all of a retiree’s income sources are payable for life, part of the plan will be taking withdrawals from an existing IRA and other accounts. Determining how much can be withdrawn each year depends in part on how long retirement will last. So making a reasonable estimate (and updating that estimate over the years) is an important part of retirement income planning.

This process begins by considering average life expectancy. According to the Social Security Commission, the average life expectancy at age 65 is almost 20 years, and there is a one in four chance of living to age 90. In addition, there are some interesting tools available on the web for making a more personal calculation. For example, the Living to 100 calculator provides an estimate based on answers to questions about personal and family medical history as well as questions about lifestyle habits.

Boomer: What is a contingency fund and what is in it?

Littell: One solution to address longevity risk, as well as other risks faced in retirement, is to maintain a separate source of funds that are reserved for these contingencies. A contingency fund can be a diversified investment portfolio. If the purpose is to have funds available if life is longer than expected, then it is appropriate to choose investments that emphasize long-term growth. A tax-efficient approach is to build this fund within a Roth IRA. With this approach, the value is not diminished by taxes and if the funds are not needed, the Roth IRA is a very tax efficient vehicle to leave to heirs.

A contingency fund does not always have to be an investment portfolio. It could also be the cash value of a life insurance policy, or a reverse mortgage with a line of credit payout option. Both of those options have limited tax consequences as well.

Boomer: How does longevity risk impact some of the other risks faced in retirement?

Littell: Some describe longevity risk as a risk multiplier. When a person lives longer in retirement, it means greater exposure to most of the other retirement risks such as inflation, increasing costs for health care and long-term care and more exposure to public policy changes that could put your savings at risk.

Boomer: How can boomers develop an income plan that evaluates all of the risks that retirees will face post retirement?

Littell: Building a retirement income plan requires strategies for creating consistent income to replace a paycheck and address other financial goals, such as leaving a legacy for heirs. But it also requires considering each of the major risks faced in retirement and having one or more strategies to address each risk.

One thing that becomes apparent when looking at all the risks is that the solutions to some risks require locking into income annuities and other low risk investments, while other risks require the flexibility of a diversified portfolio that can be adjusted based on changing circumstances over time. A critical guide for these choices is an informed advisor (such as someone who has earned the Retirement Income Certified Professional (RICP®) or Chartered Financial Consultant (ChFC®) designation from The American College) that can help you react (but not overreact) to changing circumstances.