Because people are living longer, healthier lives, they need to save enough money to last for 15 to 20 years or even longer, according to the Wells Fargo Investment Institute. Thus, it has produced a new report, “Reimagining Retirement: Generational Strategies for 21^st Century Challenges,” that lays out strategies that Millennials, Generation X and Baby Boomers can take to succeed in saving enough money for retirement.

The institute notes that younger investors expect to rely more on 401(k) and individual retirement account (IRA) savings in retirement and less on pensions and Social Security than older investors. Baby Boomers think 401(k)s/IRAs will supply 25% of their income in retirement, Social Security 38% and pensions, 19%. By comparison, Gen Xers say 401(k)s/IRAs will comprise 39% of that pie, Social Security 25% and pensions 15%. Millennials say the makeup is 46% 401(k)s/IRAs, 15% Social Security and 8% pensions.

A Wells Fargo survey found that 60% of Americans think they will have enough money to last throughout their retirement. However, 40% think they will have to work longer and/or lower their cost of living in order to get by.

The institute notes that developed economies have relatively generous benefits for retirees, but aging populations are challenging the systems designed to support them. The U.S. spends relatively less (7.1%) on retirees as a percentage of gross domestic product than Japan (10.2%) and European countries such as Germany (10.1%).

Furthermore, while the average life expectancy in the U.S. in 1900 was 46 for a man and 48 for a woman, today those figures are 77 and 81, respectively. With the average age of retirement between 63 and 64, that means that people must save enough to last for 15 to 20 years, and women are particularly challenged as they live longer and earn less than men.

Sixty-three percent of men make saving for retirement a financial priority, compared to 51% of men. Men have an average of $100,000 saved for retirement, compared to $37,000 for women. Only 25% of men are unsure of what their monthly expenses will be in retirement, but this jumps to 34% among women.

Different Approaches

Having laid out the challenges, the institute then offers different strategies that various generational groups can take to approach retirement savings.

Many Boomers may find themselves working in retirement, the institute says. In 2016, the percentage of the workforce age 65 and older was 19.3%. This is projected to rise to 21.8% by 2026. It also suggests that they delay taking Social Security benefits until they turn 70 and purchase immediate and deferred annuities that offer tax-deferred growth and guaranteed income.

The institute also suggests that Boomers consider moving to a lower-cost state or country, obtain health insurance, maintain a higher allocation in equities and rent out an extra room in their house.

Generation X is the first cohort to have access to 401(k) plans for most of their working years. A big challenge for this generation is that they may have found themselves making trade-offs between the needs of their parents, their children and their own retirement—and may have shortchanged themselves.

While Gen Xers are less confident about retirement (59%) than all workers (72%), the institute says, they still have time to grow their savings. For this generation, it suggests they create a budget and stick to it in order to juggle their many responsibilities. Furthermore, the institute says they should balance expenses with saving for retirement, consider life or disability insurance, save aggressively, take advantage of company matches and catch-up contributions, diversify their portfolio across domestic and international markets, rebalance their portfolio regularly and have an emergency fund that will cover six to 18 months of living expenses.

Millennials will bear the responsibility of saving for retirement with less assistance than previous generations, but they appear to be rising to the challenge. Wells Fargo learned that they started saving for retirement at age 24—a full decade earlier than Boomers. Furthermore, 30% save 10% or more of their pay.

However, because many Millennials entered the workforce at the time of the 2008 Great Recession, 20% say they will never invest in the stock market, and 30% are taking a conservative approach to retirement saving. Wells Fargo thinks this could hurt Millennials’ long-term prospects.

Thus, the institute encourages Millennials to take advantage of automatic enrollment and company matches, keep their retirement savings when switching jobs rather than cash out, consider a Roth 401(k), start saving as early as possible, balance repayment of student loans with retirement savings, avoid investing too conservatively and remember to maintain global diversification.