Aenghus
Explorer
23 in a 3rd ed game as a DM, 14 in a 2nd ed game as a player, from 1st level. I'm DM almost all the time, so have limited chances to play nowadays.
I've played in high level campaigns that started at high level though, 18th level in a 2e game and 31st level in an epic 3e game, ending at 33rd level.
I find the limiting factors in such things are groups breaking up due to new jobs and other real world issues, or referee burnout.
Groups are very idiosyncratic in their campaign lengths, some games run in the same setting for decades with different parties, others run lots of short campaigns with huge amounts of variety in setting.
I've played in high level campaigns that started at high level though, 18th level in a 2e game and 31st level in an epic 3e game, ending at 33rd level.
I find the limiting factors in such things are groups breaking up due to new jobs and other real world issues, or referee burnout.
Groups are very idiosyncratic in their campaign lengths, some games run in the same setting for decades with different parties, others run lots of short campaigns with huge amounts of variety in setting.