With this in mind, let’s take a closer look at a few lessons that can be learned from those who have already entered retirement.

1) You’re probably not saving enough

According to our research, less than half of all retired Americans (40%) believe they saved enough for retirement, and 45% say their expenses are higher than anticipated.

At any age, saving for retirement can be challenging.

In your 20s and 30s, you’re likely faced with a host of competing financial priorities that include student loan debt, car payments, and saving for a house. It’s also tempting to succumb to procrastination, knowing that you may have 30 or 40 years ahead before you’ll be able to retire.

When you reach your 40s and 50s, competing financial obligations don’t disappear, they evolve. Instead of paying off your student loans, you find yourself paying college tuition bills for your children. In lieu of saving for a house, you’re making monthly mortgage payments or paying unexpected repair bills for a leaking roof or water heater.

Thanks to the power of compounding over time, the sooner you prioritize saving for retirement, the more likely you’ll have enough saved to manage your expenses after leaving the workforce. This is especially important to the millions of Americans who depend on 401k plans as their primary source of income during retirement.

2) Expect the unexpected

In 1980, the inflation rate in the United States peaked at 14.7%. In 2022, it reached 9%, and today it stands at a more manageable 2.3%.

Where the inflation rate will be when you’re ready to retire is both unknown and uncontrollable. Similarly, stocks may be in the middle of a historic bull market when you’re ready to leave the workforce or your portfolio might be negatively impacted by a bear market.

Given the unexpected nature of these events, it’s not surprising our research found that the top three concerns plaguing retired Americans in 2025 are inflation (92% of retirees are at least slightly concerned), rising healthcare costs (85%), and the potential for a major market downturn (80%).

While these concerns may be unnerving and unpredictable, they shouldn’t derail a secure retirement if you stay focused on the variables that are in your control. Your monthly savings rate, participation in a tax-advantaged retirement savings plan like a 401k, your diversification strategy, and the age at which you plan to retire are all key factors in your retirement planning that are within your control.

Creating good financial habits and making sound decisions about the factors within your control will help put you on the path toward a comfortable retirement despite short-term swings in the market or the inflation rate.

3) Winging it won’t get you there

For many decades, traditional company pension plans provided workers with a safety net that, when combined with Social Security benefits, helped to ensure a comfortable retirement. But times have changed as pensions have become a relic of the past for most private-sector employees.

The shift from traditional pensions (known as defined benefit plans) to defined contribution retirement plans has placed the responsibility for retirement saving and planning on the employee. Despite the challenges associated with figuring out when to retire, how and when to claim Social Security, or how to generate steady income after leaving the workforce, many people don’t work with a financial advisor and have no plan for managing their retirement expenses and assets.

According to our latest study, 64% of retired Americans aren’t working with a financial advisor and 44% don’t have a plan in place for estimating expenses, determining how much income is needed, and developing an investment strategy to meet their goals.

Given this lack of support and planning, it’s perhaps not surprising that most retirees (62%) say they have no idea how long their savings will last.

While not everyone needs to maintain an ongoing relationship with a financial advisor, there’s no question that anyone preparing for retirement could benefit from seeking guidance on how to improve their financial well-being and maximize their income stream once they stop working.

Retirement security doesn’t happen by chance—it requires planning and discipline. While it’s easy to postpone saving or assume that Social Security alone will suffice, our research paints a different picture. With rising expenses, unpredictable markets, and fewer guaranteed income sources like pensions, the burden of retirement planning now falls squarely on individuals. Fortunately, by taking control of the variables you can manage—your savings rate, investment strategy, and financial planning—your retirement dreams can be within reach.

It’s never too early — or too late — to start making financial decisions that will pay dividends in the years ahead.

The opinions expressed in Fortune.com commentary pieces are solely the views of their authors and do not necessarily reflect the opinions and beliefs of Fortune.