I read somewhere that Bob Copper still thought he was 29 in his head. He was around 85 externally at the time. On the other hand I saw a floor singer the other week who did a convincing external impression of being around 25 but was obviously internally a pensioner - a seriously grumpy, boring, academic blighter (and singer/songwriter too)

But in general terms - Shooting Roots set their upper limit as 25 I think. That's a good rule of folk thumb for young. Then you get a gap of about 20 years until you become middle aged, probably 45-59. Then another gap until "old", which is 75 up. What the hell people do in those missing years is hard to imagine. Bring up children and grand children I suppose.

To paraphrase a well-known cartoon: on the internet, nobody knows you're a pensioner. Unless you make comments about "punk rock" as if it happened just last week and was still topical . . .