Unfortunately, most people's time in football ends after the age of 35.
If you're lucky, your body will keep going until after 40, but that's still unlikely.
But 79-year-old Colin Lee has defied all the odds.
Lee is currently Britain's oldest goalkeeper, still playing for his local club.
He started playing football 73 years ago, when he was six, and has continued playing up until the present day.
Lee, who is a Wolverhampton Wanderers fan, has got arthritis in his hands and knees but is continuing to play the beautiful game.
“I’ve been told you have to be mad to be a goalie, so I guess I must be bordering on that as I’ve done it for so long," he told Yahoo.
“I love chucking myself around the goal like a lunatic.
“I’ve got arthritis in my hands and my joints and knees are stiffer than they used to be but I still love it when I make a good save.
“I’ve had lots of bruises but amazingly I’ve never had any serious football injuries in more than 70 years.
“I turn 80 in June and I’ve got no plans to stop playing. I will play for as long as my body lets me and of course, if I’m still picked for the team.”
He initially played centre-back but has played in goal for the last six decades.
“When I first started playing I went in any position I could just to get a game. But since 1949 I have played in goal, I just really enjoy it.
“I’ve got a knack for knowing were the players are going to shoot and it’s a matter of pride for me to get my body in front of the ball.”
Lee plays at his local club with his son, 50, and his grandson, who is 21.
“It is wonderful to play with my son and grandson," he said.
“Unfortunately Colin has the same knee problems I’ve suffered with but it’s great when we all turn out for the same team.
“I can still play a full 90 minutes but I also do a lot behind the scenes and we’re currently trying to build a new club house and community centre for the future generations.”