Most retirement advice, and most retirement planning in practice, focuses almost entirely on one number: how much money is saved. A specific longitudinal study suggests that narrow focus might be one of the most common and consequential retirement mistakes.
The clearest evidence comes from a 2017 study by Dannii Yeung and Xiao Zhou, published in Frontiers in Psychology. The researchers followed a group of Hong Kong workers across three points in time, six months before retiring, six months after, and a full year after, tracking how much preparatory activity people engaged in across multiple areas of life, not just finances but also health and social or interpersonal planning. People who engaged in more of this broader, multidimensional preparation built up greater personal resources by the time they actually retired, tangible resources like finances, but also mental and social resources. And critically, it was those accumulated resources, not simply having done financial planning alone, that predicted better psychological and physical wellbeing a full year into retirement. Financial preparation on its own wasn’t enough to explain who ended up thriving.
A second, more recent study helps clarify exactly where that gap tends to show up: social connection. In a 2025 study by Lisa Kenny, Niamh Doherty, Aisling Doherty, and colleagues, published in BMC Public Health, the researchers used the English Longitudinal Study of Ageing, tracking 3,758 participants across five survey waves from 2008 to 2017, including 766 people who retired between waves. Retirement itself didn’t increase loneliness in either the short or long term, and newly retired participants actually showed reduced objective social isolation right after retiring. But that effect didn’t persist on its own over the longer term. The researchers’ interpretation was specific: retirement doesn’t automatically make someone lonelier or more isolated, but it also doesn’t automatically protect against it either, what happens to a retiree’s social world depends heavily on what they actively do to build and maintain it, not on retirement status by itself.
Together, these two studies point toward the same underlying mistake from different angles. Yeung and Zhou’s research shows that people who only prepare financially for retirement, without also building health and social resources ahead of time, end up with less overall wellbeing a year in, even if the money itself is in order. Kenny and colleagues’ research shows why that social piece specifically matters so much: retirement creates a real opening, briefly reducing isolation right at the transition, but that opening closes again unless someone actively keeps building and maintaining social connection rather than assuming it will simply continue on its own. The common mistake in both studies isn’t bad financial planning. It’s treating retirement as a single financial event rather than a broader life transition that needs its own kind of preparation.
It’s worth being honest about what these two studies don’t establish. Yeung and Zhou’s sample was relatively small by the end of the study, 118 participants completed all three waves, and it was drawn specifically from Hong Kong workers, so how precisely the same pattern plays out in other cultural or economic contexts isn’t something this particular study can confirm. Kenny and colleagues’ research is observational, using large-scale survey data rather than an experiment, so while the researchers controlled for other factors, it can’t fully rule out that people who were already more socially resilient were also more likely to retire smoothly in the first place, rather than retirement itself driving the short-term isolation reduction they observed.
Within those honest limits, both studies point toward a specific, actionable correction to how most people approach retirement planning. The financial number matters, but treating it as the whole plan appears to be a real mistake. What predicted better wellbeing a year into retirement wasn’t just the size of the nest egg, it was whether someone had also built real health and social resources ahead of time, and whether they kept actively investing in those connections once retirement actually began.
