I try to keep all of my recent topics active, though it usually fails cause my board is going through its annual inactivity period at the moment (only the Admins and Mods are posting, and no new members are joining); it's happened ever since we were on ezboard.

Though we do have a rule; you don't bump topics back that are more than two months old, because it makes the board look more inactive than it already is. And it seems to work, too.