I agree with Denis.
After we hit 1000
Once a year purge those with zero post.
Maybe a warning if they would like to extend their membership.
It would be nice to keep the names alive of members that contributed many post, (say over a 1,000)
That has left the forum due to illness or death or even lack of interest. Maybe like a wacko Hall of fame.
That their name and contribution would be remembered always.