Every year, the pollsters at Gallup survey workers to ask them at what age they expect to retire. Back in the mid-90s, nearly half of respondents expected to retire before their 65th birthday, and only 14% expected to retire when they were over 65.

20 years later, those numbers have flipped. Now, only 32% of workers expect to retire prior to age 65, and 37% now believe they’ll retire over the age of 65.

Even though the average expected retirement age has steadily risen, the average age at which current retirees retire has generally plateaued. Over the past 10 years, more than two-thirds of retirees have retired before turning 65.

So what gives? Why is there this disconnect between an increasing number of people who are expecting to work into their late 60s and a consistent majority of retirees who are retiring in their early 60s (or even younger)?

Part of the reason, as Gallup notes, is that there may be a generational divide within the data. Essentially, the thinking goes that today’s workers expect to retire at an older age than their older peers who are currently retired. This intuitively makes sense since, historically, as lifespans have increased, so too has the average retirement age.

That said, a possible generational divide doesn’t tell the whole story. There are specific factors that can arise that can cause you to retire at a younger age than you originally planned. The most common of these are:

• Health issues: Of all the causes that may force you into an early retirement, health issues are perhaps the most likely to occur. A sudden illness can arise swiftly and unexpectedly which may force you to retire, or at the very least, reduce the number of hours you’re capable of working. Not only could a significant health event reduce your hours worked—and, subsequently, your earned income—but it could also mean that your living expenses will spike due to the higher health costs you’ll face.
• Layoffs: If your employer begins to struggle financially, layoffs may be on the horizon. Since older workers likely have higher salaries, they are often the first to be laid off. To compound the issues of a layoff, older workers can find it much more challenging to find a new job than younger workers. This can turn an expected temporary lull in employment into an early retirement.
• Caring for family: If you have aging parents whose health is ailing, the onus may fall on you to help serve as their caregiver, especially if hiring a professional isn’t financially feasible. The act of caregiving can be very time-consuming and may cause you to reduce the hours you’re working or may even dictate that you may have to stop working altogether.

The common thread of these three factors is that, generally speaking, they are all largely out of your control. This means that if your retirement income plan is to work as long as possible, it’s important that you have a Plan B in place in the event that outside factors, not you, dictate your retirement date.

This article originally appeared on February 28, 2016 in the St. Paul Pioneer Press. You may view the original article here.