SINGAPORE - In an ideal world, there would be fewer old people and many young children, all supported by a large number of able-bodied adults. This way, the strain on working adults will be minimal.
There will also be enough children to take over the work as their parents age, and everyone can lead a good life.
This was once the scenario in Singapore when it experienced a growth spurt in the decades following independence in 1965.
Not many went to university, so the majority started jobs in their late teens, retired when they were 55, and enjoyed their last 10 years living off what they had saved after 40 years of work.
In the last 50 years, many things have changed.
People today are having fewer children, so there is a smaller number of young people joining the workforce each year. Higher living standards and advances in medical science also mean people are living much longer.
In 1965, the average life expectancy here was 65. Today, it is 82, which means that people are living 17 years longer on average.
Based on current projections, people aged 65 years and older, which accounted for 2.5 per cent of the population in 1965, is expected to form 18.4 per cent by 2030.
So should you fear the greying population, or the "silver tsunami" as some have called it? The simple answer is: Yes!
If the current situation does not change, a shrinking younger generation will be left to bear the increasing cost of caring for an ever- growing group of dependent elderly.
As people get older, they will need more health-care services.
According to the Ministry of Health, people over the age of 65 are four times more likely to be hospitalised than younger adults. They also tend to stay in hospital for a longer period.
The number of people in that age group in Singapore is expected to nearly triple, from 350,000 in 2010 to 960,000 by 2030.
This means that more hospitals will have to be built, more doctors and nurses will be needed, and government spending will go up as more old people, having depleted their savings after 20 years or more in retirement, turn to subsidised wards.
Who will pay for all this? You.
That is, unless things change.
Official retirement age has gone up to 62 years from 55. But extending it by just seven years when people expect to live 17 years more is simply bad mathematics.
With about half going on to university or polytechnic, coupled with two years of national service for boys, people today usually start work in their early 20s.
This means that the actual number of working, and hence income- generating, years has gone up by very little.
So savings from four decades of work now has to sustain the person over the remaining 20 years of his life, when it was only 10 years in the past.
Many retirees may then have to turn to government subsidies when it comes to expensive health-care needs. Others may turn to their children, who have their own families to bring up.
These children, caught in a sandwich generation, will be hard-pressed to support their parents or grandparents, bring up their kids, and save for their own old age.
The government is aware of this looming issue. Companies are already being encouraged to keep workers till they are 65 years old.
But a lot more has to change, especially society's attitude towards older people.
So long as 65 remains the yardstick to label someone old and over the hill, the rapidly greying population will continue to be seen as a problem.
Singapore is not the only country facing a rapidly ageing population.
Worldwide, the number of people aged 65 or older is projected to grow to 1.5 billion in 2050, from 524 million in 2010. From forming just 8 per cent of the world's population, this group will make up 16 per cent by 2050.
Because of this, there have been many studies on older people's abilities, frailties and needs.
And these studies show that there is only a very slight drop in ability between the ages of 60 and 69.
There is some truth in the adage that the 60s is the new 40s - meaning that people who are 60 years old today are as fit as someone at 40 half a century ago.
Anecdotally, many people remain in good physical and mental health well into their 70s, and some even into their 80s.
New terms have emerged.
The "young old" are people aged 65 to 80 years, while the "old old" refer to those over 80.
Even then, geriatricians - doctors who specialise in elderly care - say some of the old-old are fitter and more alert than some adults in their 50s.
When it comes to dependency, a person's frailty rather than biological age should be what counts.
As long as a person remains fit and is able to contribute to the economy, they should be allowed to. This will help boost the total workforce.
But many of these older people, having worked for decades, might feel that it is time for them to kick back and enjoy their lives.
To cater to their aspirations as well as society's needs, companies need to adjust and allow such people to work perhaps on a part-time basis, or give them a shorter work week.
This way, they remain economically independent even as their hair grey, but are still able to enjoy more free time.
The worry would no longer be how much of the population is made up of people who are 65 and older, but rather, the actual number of frail elderly who need to be supported.