When it comes to sending birthday cards, my wife and I have a well-tested and near-perfect system; perfect in all respects except for the few times that it includes me.

You see Mrs M has drawn up a birthday list to cover various nieces, nephews and a few close friends. She has also, in her wisdom, assembled a fine collection of general cards that will suit most eventualities, and so we have the monthly treat of posting them during one of our evening walks.

Problems only arise when some awkward soul has a birthday that is a little more significant that normal - 21st etc. It is then that my wife broadens her process to include me. I am dispatched during one of my lunch breaks to find a card that expresses the correct sentiment. Simple, you would think.

We had one of these birthdays to commemorate recently when a dear family friend reached the quality age of 70. Norma Thomas was an important part of our growing-up years by offering a warm front room to her children and their friends in order that they might not just hang around the streets. She was good at baking, too, which just added to the appeal of spending an evening at Mrs T's.

Unlike most parents, it seemed to me, she was willing to allow two important things to happen in her house; we could watch Top of the Pops with the volume turned up loud, and she was happy to switch the central heating on when it was cold.

I am not sure what it is about parents but they seem obsessed with saving money on energy bills. I have now reached the age at which switching lights off is mandatory when you leave the room; even if someone is still in it.

Filling the kettle used to take no more skill than turning the tap on. Now I feel compelled to work out how much water I might need in order to only boil the correct amount. What next? Will I start wearing a vest in summer? Or winter for that matter?

Either way, my involvement - voluntarily or otherwise - was required and my wife set out clear instructions for the type of card that would fit the occasion. I had decided my own criteria, mostly revolving around price, but I felt it best to keep such thoughts to myself.

Choosing the card was a relatively straightforward process as there wasn't a lot of choice on offer. Whether that is because card manufacturers don't expect people to live to be three score years and ten or that 70-year-olds don't have friends, I am not sure. It is the same when trying to buy a card to celebrate a 30th wedding anniversary; not many seem to make it that far!

Having made my purchase I then had to think of what to write in it. I revisited the card most days for the next two weeks without actually getting to the point of posting it. Some days I couldn't decide what to write and some days I ran out of time. There were one or two times when I forgot that I had even bought a card; I think that must be an age thing too!

Every time my wife asked me whether I had sent it, I would reply with one of my stock phrases: "I am working on it." When she complained, I would leap to my defence by saying: "It's the thought that counts." She offered to take over the operation, but I wasn't to be defeated.

Eventually I settled on a minimalist approach and simply wrote You will probably never know how special you are. Happy Birthday!' My wife rolled her eyes and questioned why it would take two weeks to come up with that.

I told her that I had been distracted by another thought; it had occurred to me that I am now some 12 years older than Mrs T was when I first met her in the mid-Seventies. It is thoughts like this that make you shiver enough to want to put a vest on in summer...