When you reach the age of 65 or so, you fancy you've earned the right to put your feet up and relax. Your children are probably raised. You've paid off the mortgage. You've finished your career. The nest might be empty.
If you still have your health, you have about 15 years before old age really begins to take its toll. That's a long time in which to pursue those hobbies and pastimes you could previously only fitted in between everything else.
But life rarely works out quite as you plan. Suddenly you find that you're having to look after your grandchildren, and not just on the occasional weekend or evening but every working day.
The pastimes will have to be put on hold again.
A soon-to-be-published study has found that about 60pc of grandparents have looked after their grandchildren at some point in the last month.
Of these, one in five looked after them for more than 60 hours per month.
Those in this category were more likely to exhibit signs of depression.
In the absence of the study itself - from the Irish Longitudinal Study on Ageing at Trinity College - we don't know how much more likely they are to suffer the sign of depressions, or whether there are other contributory factors. We'll just have to take it at face value for now.
But one thing stands out for me from the information available so far. Can it be true that 40pc of grandparents haven't looked after their grandchildren at all in the past 30 days? That's nearly half, and that's a lot.
How can this be? Do they not live near their grandchildren? Do the grandparents' own children have so many child-minding alternatives to hand that they don't need to leave their own children with their grandparents for even an hour a month?
Or are some grandparents simply refusing point-blank to ever look after their grandchildren?
In fact, when you look a little closer, you find that just 12pc of grandparents look after their grandchildren for more than 60 hours a month. (By the way, that comes to an average of 15 hours per week or three hours per working day).
Therefore, it's only that 12pc which have a somewhat higher risk of showing signs of depression than other grandparents with less on their plate.
This finding of the study has been seized on to make the case yet again for State-subsidised childcare. More cheap childcare places, we are told, will allow the grandparents to be relieved of the burden of looking after their grandchildren.
That sounds like a very neat solution. It leaves out a whole lot of complicating factors, however.
For example, we don't know how many grandparents actually object to looking after their grandchildren.
We do know that the vast majority of parents prefer to have their children cared for during the day either by other family members or by the parents themselves.
In fact, an opinion poll carried out on behalf of The Iona Institute (which I run) found that only 17pc of people want to see children placed in day-care as their first option. The fact that childcare is the first option for only a small minority of parents is left out of every policy discussion about this issue.
The result is that the discussion is dominated by voices who demand the State pay for childcare or give parents big tax breaks for childcare and then proceed to brainwash parents into thinking this is the only answer.
The other factor left out of the discussion is that the more the State pays for childcare, the more that becomes the only option for parents, regardless of what they actually want.
Finally, what do the children themselves prefer? Does anyone ever even ask this question? Would the children prefer to be looked after at home during the day by their mother or father? By a grandparent? By another relative? By a child-minder? Or would they prefer to be put in childcare?
I think we already know the answer to this question, and it's not childcare.
If we then come back and say it has become impractical or even undesirable to give children what they want - care by a parent or other family member - shouldn't we take stock of where we're going and of the type of society we're becoming?
But there's another big issue at play in this discussion, and that is the absolutely vital and indispensable role grandparents and other retired people play in society.
Politicians talk about the "grey vote". They do that because they know older people vote. Older people vote because they tend to be very civic-minded.
Our society is extremely individualistic. But our parents or grandparents grew up in a time when it was a lot less so. They grew up at a time when people joined things and made strong commitments. To the church, for example. Or to a political party. Or a trade union. They were and are avid newspaper buyers.
We like to condemn their society for its lack of individual freedom, but it gave us the very people we now rely on to look after our own children and generally keep the show on the road.
We know they'll do it because they have a strong sense of duty, because that's the way they were brought up.
What will we be like when our day comes and we're asked to look after our grandchildren?
Or try this thought experiment. Imagine how sunk we'd be if one day all the grandparents in Ireland decided to go on strike?