As birthdays go, 50 used to smack of cardigans, nasty coughs and golfing carts. If 40 was the end of youth, “the big five-oh” was the dreaded number that ushered in the twilight years of cruise ships and varifocals.

But with life expectancy for women approaching 82 – and retirement age receding into the distance – 50’s resonance and significance as a birthday is changing dramatically. This year, 868,000 in the UK will turn 50; that’s 32,000 people more than in 2010. With the over-50s age group increasing so rapidly – according to the Office of National Statistics, someone in the UK turns 50 every 40 seconds – are we finally reassessing our cult of youth?

“We are welcoming an era in which 50 is the new 34,” argues Emma Soames, Saga magazine’s editor-at-large. The increasingly glamorous image of 50-year-olds has even spawned a new term, the “Quintastics” – thanks, in part, to the visibility of a number of high-profile celebrities who met the event with undiminished glamour in the past year, including Bono, Nigella Lawson, Hugh Grant, Jonathan Ross, Colin Firth, Tilda Swinton and Kristin Scott Thomas.

But it’s not all good news. “By the time we are 50, we are definitely in the suburbs of mortality,” says Alain de Botton. “After 21, birthdays are really wakes and occasions for mourning – unfairly ascribed a degree of jollity which they absolutely don’t require. Yes, older people now look a bit better for a while longer, but essentially, it’s pretty much a vale of tears.”

Nevertheless there’s something newly cool about turning 50. Just ask George Clooney – whose birthday falls in May and who has almost single-handedly ignited a revival of the Cary Grant/Spencer Tracy brand of suave older man – or Barack Obama (50 in August), still the closest thing we’ve got to a real-life superhero.

As Michelle Pfeiffer said when she reached the landmark: “You just take stock and count your blessings.”

Ian Rankin, writer, born 28 April 1960

Fifty was one of the nicest birthdays I’ve ever had. I had a week-long celebration. They held a big party for me at the Central Library in Edinburgh and afterwards we went to the pub and Kenny Anderson, who’s one of my favourite musicians, got out his guitar and started playing me a few songs. That was rather special.

It certainly wasn’t as traumatic as turning 40. I remember the last day of being 39 and feeling a mid-life slump. In 2000 I still lacked a bit of self confidence in the books I was writing. They were selling fine, but we were living in a house that wasn’t as big as we’d like, on a busy street, my kids were young and you’re thinking, “Are they going to grow up OK?” I still felt I hadn’t made it professionally. I was no longer new talent: I was caught somewhere between new and established.

But during that decade between 40 and 50, something really changed in my work. The novels that I was writing started to become more political, and I think that was due to having school-age kids – you start to wonder about the world that your generation is leaving behind for their generation. You’ve got a lot of questions and doubts, and I found a way of exploring those in my fiction. Once you are comfortable in your own skin then you start to look more at the outside world. By the time I turned 50 we’d moved into a bigger house, on a quieter street, and I wasn’t nearly so anxious.

I recently went to my first high-school reunion, in Fife where I grew up, with people who had all turned 50. We all said the same thing – that we don’t feel any different from when we were 18 or 19. We still have some of the same friends, we still listen to much the same music. The teachers, who had seemed ancient to me back then, didn’t look any different today.

Of course there are still dreams that you wish you could fulfil. A lot of 50-year-old males go through this – we yearn for the days when we could still be a successful rock star, or have a really nice car, like an Aston Martin. But some of those dreams you have to shrug off now.

And I’m very conscious that in some parts of Scotland, through factors such as long-term unemployment, poverty, social-housing issues and lifestyle, the mortality rate for men is in its early 50s, particularly in some of the less salubrious parts of Glasgow. I’m lucky that because I don’t live in those parts of Scotland I’ll maybe see my 60s as well.

Ian Rankin’s latest novel is Dark Entries (Titan Books, £14.99)

Grayson Perry, artist, born 24 March 1960

I’ve been looking forward to turning 50 – now I can feel a bit like an elder. When I was much younger, I had a conversation with an art dealer. She said that their 20s is when artists mess around; their 30s is when they make their decisive works; in their 40s they’ve made their money (if only that had been true for me – I’m a bit of a late developer in this case); and in their 50s they either consolidate their reputation by churning out the same work endlessly – and there’s plenty of artists who do that – or they get a second wind and reinvent themselves.

I’m not sure that’s me, but I do get bored with my own work quite easily so when an opportunity to try a new technique or material comes up I’ll have a go. I don’t want to get pigeonholed as that bloke who did the pots. One of the best parts of the past year has been creating my first real artefact: the Walthamstow tapestry. But my favourite memory of the year was going to Germany on my special motorbike. I took my teddy bear round Bavaria in September with a bunch of friends.

There are definitely more intimations of mortality. I’m not particularly interested in posterity, but there are things I’d like to have a go at and this is the age where experience and energy meet – your experience is going up and your energy’s going down. One thing I still want to do is design a building. That has been an aim of mine for a long time and now I’ve got to get on and do it.

When I was younger, I thought that I’d know I was getting old when I made work that was unembarrassed to be decorative – that by the time I was 70 I’d be doing lovely coloured abstracts in pretty patterns. And I might be going in that direction. I’m not a punk rocker any more, wanting to be angry for the sake of it. That seems very tiresome.

The downside of being 50 is feeling that you are falling apart physically. I was a pretty fit person until very recently and now I’m finding myself creaking too much, the legacy of too many bicycle crashes, and my back is going. The things I like doing best are going to parties and museums, and both those things involve a lot of standing around, which I can’t handle any more. Unless I get really drunk.

But I don’t think I look too bad for 50. It’s an age where all of your chickens come home to roost in terms of how you’ve looked after yourself and some people who have smoked a lot and drunk a lot can look more like 65. I was watching Mike Leigh’s Another Year recently and it struck me that not only does that apply to your physical health but your mental health, too.

For a tranny, getting old can be quite traumatic. When you’re really young there’s a certain androgyny about your teenage years so you can get away with looking pretty. Then you become more square jawed and bolder and you don’t look so pretty in a frock any more.

Now I’m 50 I’m happy to use off-road make-up and I’m much more experimental. I used to agonise about looking feminine and now I don’t give a toss. I really enjoy trying a new look.

Unfortunately I haven’t yet got to that lovely old age where you really don’t give a shit about what other people say, which I’m looking forward to immensely. I still care what people think of me, which is a terrible handicap.

Grayson Perry will be talking on Kinky Sex at the School of Life on 13 February (theschooloflife.com)

Carol Vorderman, TV presenter, born 24 December 1960

My birthday is on Christmas Eve, which means I never get a party. So I decided that for my 50th I was going to use up all the party credit I’d never spent and have 50 celebrations over the year. They’re going to include things like wing walking and tank driving and I hope it will be the most fun year of my life.

I had a big wake up-call recently. Until now I’ve been driven by a workaholic demon and the years start to blend into each other when you’re going at such a ridiculous pace. Then I had a health scare last July – it turned out I have arrhythmia, a very common problem, but at the time it gives you a worry. You start losing people in their 50s and you realise none of us can rely on being around at 60. You think: how many summers have I got left?

So this year I’ve come to appreciate what I have, especially my amazing children, and my mum. When things go wrong, I think: “I’m not going to be down about that.” My daughter Katie was 18 in May, and one of the things I say to her is to make the most of every year while she’s young and not fret about whether your bum looks big – come 50 you’ll be wishing you still had that bum!

I’m purposefully doing things differently. I’m normally too busy to go out much, but now I’ve started saying yes to many more events – and enjoying them. I’ve discovered a penchant for all-nighters. It turns out I’m a party animal, and I really enjoy hanging out with students. I love being “Auntie Carol”. And our generation is lucky that we can still be stylish at 50. In the old days, it was elasticated waistbands and that was your lot.

What I don’t want is for 50 to become the new 40, because that puts a whole new pressure on people again, back into the melee of competition. I’m part of the first full generation of career women, and most of us realised in our 30s or 40s that even if you tried your damnedest you couldn’t have it all. But at 50 having it all is not even a question.

Carol Vorderman runs a maths tuition programme at themathsfactor.com

Linford Christie, athlete, born 2 April 1960

Age ain’t nothing but a number. The way I see it, every birthday’s a good one, because the more you have, the longer you live. I enjoy being 50 because now I can appeal to both ends of the spectrum – the older ladies and the younger ones…

When our parents were 50 they seemed really old – it was totally different from how it is for us now. We’ve got it a lot better: medical care, access to exercise, more time. I think 50 is the new 30.

I don’t even know what a mid-life crisis is. I still keep myself very fit; I work out almost every day, so, thank God, I have no aches, pains or illnesses and I’m in pretty good shape. I don’t feel much different now than I did 20 years ago.

They say wisdom is at the feet of the old and I wish I’d known what I know now when I was younger. I’d rule the world! I’ve had so much experience, both good and bad, from my life and from my career. The interesting thing is that now I’m an older person, the young athletes I coach tend to confide in me more. It probably helps that I don’t look 50. I can do both things, be a mature person or a big kid. And that’s what young people like to identify with – someone who is not like their parents.

All my goals in life were athletic so I don’t really have any anymore, I just take each day as it comes and don’t think too far ahead. What’s really changed is that I’m more interested in helping others to achieve. I think at 50 you tend not to be so selfish, you don’t think about “me” all the time.

I just want to live long enough to see my young kids grow up to be independent and happy, and to be able to kick a football with the grandkids.

Matthew Bourne, choreographer, born 13 January 1960

Turning 50 last January was exciting and positive – an achievement. I’ve always loved the idea of getting older. When I was a kid I used to hope I’d live into my late years and become an old eccentric wandering around London.

I think it depends on the world you live in – working in dance has its positive and negative sides: I’m almost always the oldest person in the room, which can make you more aware of your age, but working and being friends with a lot of the dancers, I think, keeps me young.

I had a lot of fun when I was young, I studied dance later in life, and I did Swan Lake when I was 35, which I guess you could call my breakthrough success. I never really expected to be doing what I’m doing in my life – it’s been a wonderful surprise.

I haven’t been through a mid-life crisis yet. I do think it exists, but it hits people at different times. Turning 30 or 40 can be more fraught, but by the time you turn 50 things relax a little more; I feel very content now.

I’ve been watching a lot of old footage from the 1940s recently – not of film stars, but of real people – and what’s struck me is how old everyone looked. No grooming, or looking after oneself. It seemed like everyone just gave up after they got married and had children.

What I’ve become aware of since turning 50 is that I question what I’m going to wear a lot more. Am I too old to wear this or that? I fear that I’ll be that older guy in the room that everyone rolls their eyes at and thinks, “What has he got on?”

In my mind’s eye, I’m still a lot younger than I actually am. I don’t mind looking my age: I don’t want to change the way I look, but I do avoid looking in shop windows these days. I take good care of myself: creams, lotions, anti-wrinkle this and that. If I don’t do it now, it’s probably not worth doing it at all!

Getting older only matters if you don’t feel good in yourself. You can use it as a reason to celebrate, or a reason to get depressed. For me, it felt great – a definite time to celebrate.