realistically, you should take the ones that have never posted, or have very little posts and that have not shown activity for like 6 months will lose their account and have to resign up.
When I used to be part of this integra club, I found that if I didn't post after a while, it would delete my username and I would have to resign up again. Of course this happened to me, because I sold my car, and then never really logged in for about a year. When I tried, it told me to re-sign up again.
13 year old has a valid point, but 1 month is not a long time. Heck, what if I took some vacation for a month? I'd come back and lose all my posts
I'd say the system should be cleaned 6 months to a year and clean out all the idle accounts.