For the past week, I have been shuttling between visits to my father in hospital and my mother in the care home where she now lives.
My father was 100 last December. My mother is two months away from her 95th birthday.
When I was a child, in the 1950s, or even a teenager in the ’60s, it was almost unheard of for somebody to be retired and have one parent still alive, let alone both.
Life expectancy was so much shorter then (my parents were both orphaned by the time they were in their forties). But now it is becoming, if not the norm, then certainly more prevalent.
When my father was approaching his 100th birthday, a man from the Department of Work and Pensions called to make the arrangements for him to receive a letter from the Queen on his birthday.
The man from the DWP said he used to make about three of these visits a year; now he was doing one a month.
It is a great privilege to have elderly parents. I have seen the grief and anger caused when parents die too young.
I have had the time to talk to my father about his experiences working in a Welsh tinplate works in the 1930s, and his time in the Army in the second world war.
My mother would reminisce about leaving school at 14 to train as a hairdresser. She and a friend, who was learning to be a seamstress, would walk miles every morning from their village to the shops where they were being trained. In the evening they would walk back. They were not paid. In fact, their parents had to pay the shopkeepers to take them on as trainees.
Talking to them about their early lives left me in no doubt how comparatively privileged and easy mine was.
But there are consequences of having parents who live into quite advanced old age. You watch helplessly as their health declines. Crises, small and large, happen with increasing frequency.
When they do, your own plans and arrangements must be changed. This happens to me. It happens to retired friends who are also fortunate to have a living parent.
You accept the disruption. Of course you do. They are your parents. You owe them your existence, literally.
But let us be honest with ourselves. You feel the frustration when yet another plan has to be abandoned. And, in your worst moments, there is almost what can only be called resentment.
I suspect only a saint could avoid these moments. Few of us are saints.
The rest of us who are retired with parents carry on, with our feelings of gratitude and guilt.