Mental Health Awareness Week ran from 11 to 17 May this year, with the Mental Health Foundation setting the theme as ‘Action’. It is a useful prompt for something that often gets left out of retirement conversations. Most planning focuses on the financial side. Sit a little further back and a different picture comes into view. The people who seem to enjoy the second half of life the most are not always the wealthiest. They are the ones with company.

This is not a casual observation. The evidence behind it is strong and worth reflecting on.

Why friendship belongs in the long-term plan

Researchers who have followed adults across decades, most famously through the Harvard Study of Adult Development, have arrived at a striking conclusion. The quality of someone’s relationships in midlife turns out to be one of the better predictors of how well they age. Close, supportive ties are associated with better health, sharper cognition for longer, and a happier later life. Loneliness, by contrast, behaves a little like a chronic health risk in its own right.

Other research points the same way. Studies on the so-called “Blue Zones”, the small pockets of the world where large numbers of people live into their nineties and beyond, keep landing on a familiar list – a sense of purpose, gentle daily movement, food they grew themselves, and regular social contact. The first three get most of the attention. The last one may do more of the work.

If money is one form of capital, this is another. Call it social wealth. Like financial wealth, it compounds quietly when looked after, and it can be neglected without anyone noticing until quite a lot later.

The early-retirement question

There is a question worth sitting with for anyone planning to step away from full-time work in their fifties or early sixties. Where is your weekly company going to come from when the office stops providing it?

The default architecture of midlife friendships in this country is largely built around two settings: workplaces and the school gates. Retire, or watch the children leave home, and a sizeable share of the casual contact that holds friendships together quietly disappears. National data from the Office for National Statistics and the government’s Community Life Survey both pick this up – the people most at risk of feeling lonely are not, contrary to assumption, the very old. They are people moving through transitions. Retirement is one of the larger ones.

For early retirees with means, the risk has a particular shape. The structures that produce friendships without conscious effort, the colleague who suggests lunch, the conversation in the kitchen, the parents on the touchline, retire when you do. Replacing them is doable, but it tends to need a bit of intention, and the people who do it well usually start before they need to.

What investing in social wealth might look like

The financial planning framework translates surprisingly well here, along with a few ideas borrowed from how we talk about money.

Small, regular contributions beat heroic one-offs. The Tuesday walk. The Wednesday lunch. The book group that meets whether or not anyone has read the book. Boring on paper, durable in practice.

Diversification matters. A single, intense friendship is wonderful yet also fragile. Networks that span generations, settings and intensities tend to be more resilient. Younger friends keep things current. Older friends remind you what you already know. Acquaintances, who get a bad press, often do disproportionate work in producing the daily texture of belonging.

Volunteering is the underrated answer to a lot of questions about purpose in retirement. The picture from the research is consistent – people who give time regularly tend to report higher wellbeing and better health.

And, with apologies for the pun, an annual rebalancing review is no bad thing. Once a year, a quiet half hour with a notepad is enough. Who are the people who lifted you in the last twelve months? Who have you not seen in a while that you miss? What is one thing in the diary, recurring, that puts you in a room with people you care about?

Where this meets the financial plan

The reason this sits in a financial planning newsletter is not because we have wandered out of our lane. It is because the financial plan exists to fund a life, and the life it funds is largely made of the people in it.

Wealth, carefully built and well looked after, buys something rare – the freedom to choose what to do with the next two or three decades. Time, control, and the absence of work as the dominant rhythm of the day. Those are the inputs from which social wealth gets built, if you decide to build it. The financial plan keeps the lights on. Friendship is much of what makes the room worth being in.

If this month’s prompt is ‘Action’, a small one is enough to start with. One walk. One phone call to someone you have been meaning to ring. One date in the diary that recurs. Most people who do it wish they had done it sooner.