I bought a bike once,.. with less than 4k miles on it,.. and it was 23mm out on the cam plunger...
My personal bike, was 21mm out at 24k miles...
(both,.. somewhat past the safe area)... and both got a Versy modded plunger...
I believe it is very dependent on whether you do short, errand rides, or longer (25 mile +) rides... and, secondarily, the frequency, and quality, of oil changes...
...(I would imagine also,.. the amount of hard accel and decel.... excepting that,.. I'm sure I do that a great deal more than an average noobie rider, and mine lasted for 24k miles,... against a noob, female rider, with only 4k miles, practically ruining one)...
Unless,... my 97' has a better quality chain than an 03'?..
...
...(I think It just took a mental Australian "walkabout"...)...
...
That's what comes of typing ahead of my thoughts...
...