Alistair Berg | Digitalvision | Getty ImagesPlanning to work longer is a popular escape hatch for Americans who feel they’ve saved too little to support themselves in old age.About 27% of workers intend to work in retirement because they need to supplement their income, according to a new CNBC and SurveyMonkey survey. They polled 6,657 U.S. adults in early August, including 2,603 who are retired and 4,054 who are working full time or part time, are self-employed or who own a business.While working longer is among the best ways to shore up one’s nest egg, the plan may backfire, according to retirement experts.Workers may not be able to work into their late 60s, early 70s or later due to an unexpected health complication or a layoff, for example.”It sounds great on paper,” said Philip Chao, a certified financial planner and founder of Experiential Wealth, based in Cabin John, Maryland. “But reality could be very different.”If workers lose those wages, they’d have to figure out another way to make their retirement savings last.Workers often retire earlier than plannedResearch shows Americans often stop working earlier than they anticipate.Since the early 2000s, there has been a consistent gap of about five years between retirees’ reported retirement age and workers’ expected retirement age, according to an annual Gallup poll.For example, in 2023, the average non-retiree expected to retire at 66 years old, Gallup found. However, the average retiree actually retired at 62.More from Personal Finance:The ‘billion-dollar blind spot’ of 401(k)-to-IRA rolloversSocial Security increase for 2025 could lowest since 2021How high earners can funnel money to a Roth IRAThe Employee Benefit Research Institute also finds a “large” share of retirees — 46% — leave the work force earlier than planned.A third of workers said they expect to retire at 70 or older — or never, according to EBRI’s 2023 Retirement Confidence Survey. Just 6% of retirees actually did so.A nonexistent ‘escape valve’Americans generally use a later retirement age “as an escape valve which doesn’t necessarily exist,” Chao said. “But saying it and …