It was so easy when the children were tiny. You rang someone's house, and you knew who was on the other end. Little ones, after all, have little voices.
But suddenly, once the offspring hit teenage years, phone conversations become totally baffling. You can't tell who's who.
You're generally on safe ground with a mobile. You've got a pretty good idea who's going to answer. (Although not always. I once had a rather bewildering conversation with my friend's 15-year-old daughter about why she hadn't answered my text.)
Landlines, on the other hand, are a nightmare.
It normally goes like this:
(unidentifiable voice): Hello.
(me, not having a clue, but not wanting to offend anyone): Is that...?
(unidentifiable voice) Hello?
(me): Don't worry, I'll call back later.
After all, there's one 13-year-old boy who will never speak to me again since I called him Jane.
It's probably this grinding embarrassment that makes it impossible for teenagers to remember to pass on messages.
For many years, my mother waited with mounting anxiety for me to return phone calls I never realised she'd made in the first place.
So I made it a new house rule that messages had to be written down. I even bought a small notebook and left it by the phone.
It didn't work. The notebook began as a beautiful log of calls received via BT.
It then disintegrated into a forum for general abuse as teenagers 1, 2 and 3 commented on each other's secretarial skills. Complete with cartoons and helpful diagrams.
In fury, I binned the notebook. Which didn't help at all. From then on, I had to hunt for messages on the margins of gas bills.
Son no. 2 once helpfully wrote on a piece of torn wrapping paper, 'Some woman called. Forget who. Didn't give number.'
Basically, the world has changed since everyone got mobiles. The assumption is that only unimportant calls (call centres, wrong numbers, my friends) arrive via the landline. So I can sort of see why teenagers don't bother to write down messages.
I suppose I should be grateful that anyone picks up the phone at all. The other night, as I was draining a vast vat of spaghetti into the sink, it rang and rang and rang.
'Can't anyone hear that?' I yelled, red-faced with steam.
But I think they were all too busy texting.