Making birthday candles might be a smart business to get into. New figures from the US and Britain show there's been a dramatic rise in the number of people who live long enough to blow out 100 candles on their cake.
The most recent census shows there's been a 66pc increase in centenarians in the United States, with more than 53,000 people aged 100 or over. By 2050, it's predicted that this figure will explode to 600,000.
Britain is seeing a similar trend. There's been a five-fold increase in the numbers reaching their 100th birthday over the last 30 years.
And Ireland won't be outdone. Our last census recorded 389 people aged over 100, almost 13 times the number in 1951. Remarkably, 85pc were female.
Dr Roger O'Sullivan from the Centre for Ageing Research and Development in Ireland believes that this is because women are more careful about their health.
"Women are more likely to visit their GP more often," he says. "They're also often more engaged in their social networks, which is also beneficial to their health."
"One in three children born today will live until 100," he continues. "The Government needs to think about implementing policies to do with things like work, healthcare, transport, pensions, and home and residential care."
So what's life like at the grand old age of 100? We asked the families of two who have passed that milestone.
Bridget Allen turned 100 on September 8. She lives with her only child Frank and his family in Galbally, Co Limerick. She has three granddaughters and two great-grandchildren.
Bridget was nine when Michael Collins was shot, but can still remember the shock her family felt when the news reached their home near Mitchelstown.
The killing of 'The Big Fella' dominated the conversation for weeks, as Bridget's family were great admirers of his.
But despite being a witness to historic events, Bridget prefers not to dwell on days gone by. Her son Frank thinks this attitude is one of the reasons that she has lived so long.
"She's always looked to the future, not the past," he explains. "Her grandchildren and great-grandchildren are her life and they keep her young. She's always talking about them and really brightens up when she meets them and hears their news. She even chats on Skype with one granddaughter, who lives in Australia"
Frank says that his mother genuinely never expected to live so long. She went through a period of bad health in the 1950s, but recovered.
"She never thought about turning 100 until she was in her 90s," says Frank. "When she thought it might be a possibility, she became more positive about ageing."
Bridget was always an active woman. She married a farmer at the age of 35 and spent her time milking cows, feeding calves and keeping hens and turkeys. She kept her mind active as well and was very well read on current affairs. It's an interest she maintains to this day. She watches the news on TV and reads the paper every day.
Frank says people have often asked his mother what her secret is to reaching 100, but she never offers a clear answer. "She just says, 'well I've just lived this long and that's it'," says Frank. "But good genes must have a lot to do with it. Most of her brothers and sisters lived until their 80s and she had a cousin who reached 98."
Her longevity might also be down to her interest in reading up on nutrition.
Although she's partial to the odd biscuit and has to have sugar in her tea, Bridget has always been careful about what she eats and knows a lot about what's healthy and what's not. She's not a big drinker either, although occasionally enjoys a sherry or a drop of brandy.
Frank says his mother was nervous as she approached her 100th birthday in September, as she's always been reluctant to be the centre of attention.
The family had a special mass for her that day, followed by a party in the local pub.
"She was happy once she knew the party wouldn't be in her home, as that meant she could leave any time she wanted. But in the end she stayed until half past 10," laughs Frank. "She really enjoyed herself and recognised so many people."
Even at 100, Bridget insists on staying active. "I've offered to move her bedroom downstairs, but she wouldn't hear of it," says Frank. "So she goes up and down the stairs three or four times a day.
She has a walking frame and if the day is fine she goes for a walk around the yard. She often doesn't go to bed until around half past eleven, and if The Late Late isn't over by then, she'll stay up even later."
"She doesn't dwell at all on the fact that she might be slowing down," says Frank.
"And at her age, of course she has had to say goodbye to so many people, but she looks at life a little differently. She prefers to think about those who are still around her instead of those who have already passed away. That attitude must have helped her reach such a great age."
John Lenihan turned 100 on October 16. The father of five has lived his whole life in Kilmallock, Co. Limerick. He has 14 grandchildren and two great-grandchildren.
John Lenihan was a great footballer in his youth and played on the Limerick team.
His sharp memory means he can recall events -- both good and bad -- very clearly.
"He has a friend who is also going to be 100 soon and they played a match together about 70 years ago," says John's son Michael.
"They were furious with a decision by the referee and when they get together they still talk about it. I'd say if they meet that referee in heaven someday, they'll be having words with him!"
Living a long life is definitely in John's genes.
"His own grandfather lived until he was 96 and that would have been in the days before tablets," says Michael.
John's 100th birthday was something he was nervously looking forward to.
"He was excited, but he definitely felt under pressure to reach it as well," Michael remembered. "As he got close, it would have been very disappointing for him to fall short!"
Michael says his father was a 'wiry, hardy type of person' in his footballing days.
"I'm told he was very fast and could jump and catch any ball. A lot of people at the time said he was the best footballer around."
He has slowed slightly since getting a hip replacement at 95 but still loves to get out and about and keep abreast of local news.
He delights in his grandchildren's achievements and attended two of their graduations in Cork last year.
As well as being blessed in the genes department, John puts his longevity down to drinking a pint of milk every day. He's never smoked and is only a casual drinker, but has never been particularly careful with his diet.
"He could eat a whole box of chocolates," laughs his son. "It never seems to have affected him."
John can recall events of his childhood very well. One of his earliest memories is of an ambush on the Black and Tans near his home.
"He was out on the road and heard the shots being fired. He was afraid he might get shot himself," says Michael.
His older brother Tom was involved in the ambush and John remembers him fleeing the house when the Black and Tans came to search it the following day.
He remembers the War of Independence very well, especially the way it split families who had differing viewpoints.
He saw Eamon de Valera at a rally in Michelstown and remembers how popular he was at the time.
"When he came to power there was a spell of very fine weather," says Michael. "My father can remember people saying at the time that that was down to De Valera."
Michael says his father is a much-loved part of the family but admits there must also be a downside to living so long.
"He's seen a lot of his friends dying. That's hard and it must be lonely at times," he says.
"But my father is a very positive man and he doesn't live in the past.
"He loves being around young people and being involved in their lives.
"I'm sure that attitude must have helped him to live such a long life."