You might want to consider the inactive users as it
users last seen here. Not
when they last posted. Because with any forum community, you will get your far share of lurkers (accounts that watch, but rarely post).
The other thing to consider is what to do we do with Banned Users Name as they are another type of inactive user.
Like the last thing we need is the miss conception of a new user taking using a same user name of some one be previously banned.
Eg. Lets say we get some one else signing on with the name Powerslave or Roo.
Like this will cause a lot of confusion with other users there.
Not to mension the banned users just waiting it out and claiming back their old user name.
And finally, now that we have these inactive users getting deleted. What happens to their posts. And what happens to them when some one else decided to create an account with that same user name.
This would be easy for the number of no post wonders that sign up here. But once one these users makes a even one post, then that is where a problems can start.
Sorry to bring these points up, but I work this account and point of sales software and just deleting some thing out of a datebase can not be as simple as it sounds. As it normally leaves a hole.