Some of my fondest memories of friends should, by rights, be entirely forgettable. There was that time we took our books to the park and dozed. The time we sat by the sea drinking coffee, watching the waves. The time we assembled my flatpack furniture (well – I watched), ordered a pizza and watched TV.

Fifteen years ago, these open-ended hangs were effortless and my social life flowed with only the lightest steer. Fast-forward to now, and – whether it’s the difference between being in my 30s versus my 20s, or 2023 versus 2013, or a pile-up of both – often the best I can manage is a quick drink after work in three weeks’ time. No one, myself included, is ever free to just hang out. “I’d love to,” I say, sincerely – but there is always a “but”.

The author and academic Sheila Liming wants us to find the time – or, more precisely, to reclaim it. Her new book, Hanging Out: The Radical Power of Killing Time, is partly a paean to the pleasures of idling with others and partly a manifesto to “take back our social lives from the deadening whirl of contemporary life”.

“When we’re young, it feels like social interactions just create themselves: they happen organically, we run into each other,” says Liming, at home in Vermont, when we speak over Zoom. “As we get older, they seem like something we have to put more effort into. Meetings become more structured, at times more formal – and also more of a chore.”

There is a desire, she says, “for more casual interactions that don’t have a lot of ‘objectives’ associated with them, where there is nothing in particular you’re trying to get out of it”.

Liming proposes a return to hanging out – “more amorphous and looser” than parties, but in a world obsessed with outputs, perhaps of greater importance. Liming defines hanging out as: “any time that you find yourself killing time in the presence of others … It can be something really informal, like sitting on your friend’s sofa and having a cup of tea.”

Rather than a particular activity, Liming says, it is an approach to socialising. For her, the gold standard was modelled by a colleague who invited Liming and her partner over for lunch. When they called to say that they were 20 minutes away, their host responded with enthusiasm, saying he would get started with the food. Then he asked: who was calling, sorry? Liming’s friend was willing to make lunch for anyone with his phone number.

This was several years ago, she adds. “A lot has changed.” These days it may feel like we don’t have time for lunch at all, let alone to prepare it for friends who drop by.

For office workers, technology and the associated expectation of round-the-clock availability have led to lengthening working days. Rising living costs have added to the pressure, with a reported 5.2 million UK workers taking on second jobs to cope.

Leisure time, shrinking since the 1970s, is increasingly precious for women in particular, with US and UK statistics showing a stark gender gap: a reflection of uneven distribution of caring and domestic responsibilities.

What free time people do have, time-use surveys consistently show, is mostly spent watching television – perhaps because we find ourselves too exhausted to do anything else.

The barriers to hanging out go beyond simply finding the time and the energy: increasingly, they are structural. So-called “third places” – those in which you can comfortably spend time outside your home or office – are disappearing due to factors such as public spending cuts, privatisation and gentrification. In big cities it can be a struggle to find places to just be together. This creates a vicious cycle of needing money to spend time with friends, and needing to work to make money.

This comes at a cost, Liming argues. When busy schedules mean plans are made long into the future, they can’t help but be crushed under the weight of expectation. By the time it actually happens, “I’ve almost talked myself out of the opportunity to enjoy it,” she says.

The quality of our company is just as important as the fact of it, Liming says. “We’ve all had those experiences when we’re around someone who doesn’t quite have the time to interact with us socially. That feeling of being squeezed in between two things – of being an obligation.”

I’m flooded with uncomfortable memories of events where I’ve had one foot out the door – mentally, physically or both – because I have tried to cram too much in: “stopping by” at two parties, or accepting a dinner invitation even though I’m on deadline. Seeing my grimace, Liming laughs. “It’s OK, it’s not personal. We all do it.”

It is the upshot, she says, of a culture that is continuously pushing us to wring out every bit of value from our days and to “optimise” our lives. Those pressures have filtered down to our friendships.

The pandemic hasn’t helped. “It’s like those muscles that I had previously strengthened through social interactions were flabby,” Liming says. Indeed, many people report that their circles have shrunk since Covid-19 – a YouGov survey last year found that 40% of Britons aged 16 and over had lost contact with some of their friends.

Meanwhile, the number of “kinless” adults – those who find themselves without immediate family members in later life – is expected to grow.

Yet amid this reported epidemic of loneliness, there is increased understanding that relationships are essential to our mental and physical wellbeing. Social isolation and loneliness can lead to an elevated risk of heart disease, stroke and premature death, according to a 2020 report from the National Academies of Sciences, Engineering and Medicine in the US.

Liming proposes hanging out as a balm that forges connection and meaning. The first step is is to seek to nourish our relationships – not simply to renew them as we might a TV licence. “You have to set that time aside and make sure you’re doing it justice when you get the opportunity,” she says. That may mean politely declining those invitations you would only be attending out of obligation, so as to free yourself up for the ones that matter. Liming shudders to recall how many colleagues’ and distant school friends’ baby showers she got “roped into” attending in her early 30s.

Relationships that we wish to maintain need not only time but space for intimacy, growth and even potential conflict. Liming writes of a disagreement she had recently with an old friend. After three hours, they had found common ground and Liming felt as if their “relationship had grown tougher somehow”. Had either of them been less invested, it might have been tempting to simply let the relationship cool. That is the muscle built by hanging out, says Liming, extending our tolerance for discomfort and our capacity for compassion.

It is also about letting go of expectation. Hanging out doesn’t always have to mean “a perfect party scenario or gathering; it can be just OK”. Liming gives the example of her best friend from childhood, who now lives on the opposite coast and has two young children. When they meet Liming goes along with her friend on errands or to appointments. “Just seeing her in her daily life is much more interesting to me than a sort of forced environment,” she says.

This is how I too stay connected with faraway friends, who I see on average once every two years. Where I used to try to catch up on everybody’s lives over an evening, as though I was cramming for an exam, my preference now is to dip into a few of them. I have tagged along to my sister’s work drinks, attended friends’ family gatherings, kept them company on their commute. It allows me to picture their days and engage more fully when we are apart.

When schedules do not allow for sprawling socialising, or even face-to-face,“hanging out on the internet is just what we have to do”, says Liming. Certainly, in my experience, some digital interactions can be more rewarding than others – a few of my group chats on WhatsApp are nearly as free-flowing a source of entertainment and support as being together in person. This fits Liming’s thesis that hanging out is mostly a mindset, emphasising presence over merely being present.

That can extend to interacting with those whom we often see but don’t count as friends: the staff at our favourite cafe or the familiar faces at the gym. A recent large-scale study found that having a diverse “social portfolio” was predictive of happiness and higher wellbeing.

There are certainly risks to striking up conversations with strangers, or even allowing ourselves to be vulnerable with friends, Liming acknowledges. But: “What’s the worst thing that’s going to happen?”

In the weeks after we speak, I experiment. I spend Saturday afternoon running errands with one nearby friend, then Sunday morning on Zoom with an old faraway one. I make a point of spacing out my work calls to allow for chat. I leave for yoga 10 minutes early and say hello to the instructor before class.

I don’t create any more hours in my day, but I feel the difference. My new schedule allows space for possibility: to run into a friend and not have to rush off, or to receive a last-minute invitation and reply: “I’d love to” – no buts.

Hanging Out: The Radical Power of Killing Time by Sheila Liming is published by Melville House (£20). To support the Guardian and Observer order your copy at guardianbookshop.com. Delivery charges may apply