For most retirees, plans might include a spot of golf, taking up pottery or going on Mediterranean cruises. But what if you retire before you are 30?
The Olympic athletes bowing out after London 2012 are taking the plunge into the unknown.
Some will be snapped up as pundits, consultants and sponsorship deals. They can become coaches, do speaking tours and write motivational books. But some face an uncertain professional, physical and financial future.
Swimmer Michael Phelps is bidding farewell to the pool, and planning to take up golf
For US swimmer Michael Phelps, who has hung up his speedos after 18 Olympic gold medals, the world is his oyster. "I finished my career the way I wanted to. I think that's pretty cool."
At 27, the Olympian is taking a gap year, hoping to see more of the world than just "the pool and the hotel", he told National Public Radio.
And he will also be featured on the Golf Channel, as he works to improve his handicap and try and win some golf championships, coached by Tiger Woods' mentor Hank Haney.
He said: "I'm excited about this project with Golf Channel and I'm looking forward to working with Hank and see what we can do together on the golf course."
Golf is one of the new sports to be included in Rio 2016, so Phelps may not yet have won the last of his medals.
But one athlete who has decided London 2012 is the final lap for her is Team GB cyclist Victoria Pendleton. She said in a tearful final interview: "I'm just so glad that's it all done and I can move on."
She is one of the retiring athletes with a promising media career ahead, with experts predicting the beautiful cyclist could make around £1m advertising fashion and beauty projects, although her agent Chris Evans-Pollard said Pendleton had no firm plans.
She currently endorses Halfords bikes and Hovis bread.
Victoria Pendleton is expected to earn £1m from endorsements
Ben Ainslie, the four-time gold medallist, has suggested he will also be glad to retire from sailing. He said: "I can’t sail these boats any more, it is killing my body. I would be surprised if you see me in Rio. This is the best way to leave it, on top, winning a home Olympics. It will never get better than this.
“These have been the hardest two weeks of my life. I have not slept much, especially the past couple of days. You just have to deal with that and it’s a case of getting the job done.”
Pendleton and Jessica Ennis have made fortunes in sponsorship and endorsements, with spots reserved for them on prime-time chat shows, but other athletes have shied away from the limelight, suggesting they may seek new careers away from the cameras.
Although she is completing a PhD in criminal law, Katherine Grainger, the gold medal-winning rower, has admitted she feels "like a different life is beginning and I don’t quite know how to live it."
She told the Telegraph: "For the last three months before London 2012, I was on training camps - three intense training sessions a day.
"In fact I don’t even know how I will get home to Maidenhead! In a way it is very daunting to lose all the structure and the mad excitement that taking part in the Olympics provides.
"It is hard to imagine life outside rowing, right now.
"I won’t be hanging around for long though, because the deadline for completing my PhD is in six months’ time, so that will force me to get my feet back on the ground."
She is not the first athlete to find a career in academia. Roger Bannister, who first broke the four minute mile, became a neurologist and the Master of Pembroke College, Oxford.
Some of Team GB's 2012 stars are leaving because they will be too old to compete by the time Rio 2016 rolls around.
Beth Tweddle has said she will be too old to compete in Rio 2016
Some are leaving as their age is against them, including 27-year-old British gymnast Beth Tweddle, who says her body cannot hold out for another four years until the 2016 Games in Rio de Janeiro.
"It finishes my career perfectly," said Tweddle after winning a bronze medal last week.
"I can definitely sleep easy. I haven't decided exactly what I'm doing.
"These last few weeks have been so stressful. Going to sleep with butterflies and waking up with butterflies. It was because it was my last chance."
Tweddle does not plan to give up her leotard just yet, and says she will know when she gets back on the bars whether her body can take her continuing to train.
The anxiety that comes with retiring with an uncertain future can trigger depression. And stopping exercise when an athletes consumes up to 10,000 calories a day can mean bodies change shape rapidly.
British gold medal cyclist Bradley Wiggins has spoken about how his father Garry died of alcoholism, depressed after quitting his career as a professional cyclist.
The Journal of Sports Sciences found 35% of 234 elite athletes were "exercise dependent" and that stopping could trigger depression and anxiety.
Withdrawal symptoms can also mean athletes retire - and then return to the sport, like British rower Sir Steve Redgrave. Sir Chris Hoy has not ruled out competing in Rio 2016.
The International Olympic Committee IOC works with Adecco to give athletes career counselling and a spokesman for the British Olympic Association said it was something they hoped to launch.
"We don't have such a programme right now, but we've identified it as an area we want to work on, and Sarah Winckless, chair of the athlete's commission, is looking in to it."
Dame Kelly Holmes, who retired from athletics in 2005, has created the DKH Legacy Trust to help athletes build new careers.
She has built a career as a pundit, as has Sir Steve Redgrave, who has also started his own rowing academy. Roger Black, who won two Athletics silvers in Atlanta, has also carved a TV career.
Australian swimmer Ian Thorpe struggled with his weight after leaving swimming, but has since started training again and was the star of the BBC's Aquatics Centre coverage.
Ian Thorpe had to get back into shape after quitting swimming training and putting on weight
He has funded Ian Thorpe's Fountain for Youth in 2000, which sponsors a school for orphans with disabilities in Bejiing, and also works to improve living standards in aboriginal communities in his home country.
For those who crave the spotlight, and want another highly stressful and probably short career, politics could come calling.
Locog chair Sebastian Coe was an athletics gold medallist and then a Conservative MP before he became Lord Coe, but lost his seat in the 1997 general election.
He returned to head the London 2012 bid in 2004, with his athletic credentials considered key to securing the Games for London.
Who knows, in 2040, it could be Dame Beth Tweddle leading the way for Liverpool 2044?