We recently cut down from 13 to six, for me, my wife and two kids in their 20s who keep their bikes at my house. I kept my Atlantis, Rambouillet, Cannondale MB and an old Trek converted to singlespeed, and my wife has a road bike and mountain bike she rarely uses. My son moved his Bridgestone out, I sold an Allez to a friend and we donated my daughter's bike, which she hadn't ridden in five years, and some low-end rides to a local charity (an '80s Hard Rock, Diamondback Sorrento, stuff like that). I can't really justify even the four I kept--I ought to dump everything else and just keep the Atlantis, which is pretty versatile. But screw it, we have the room and they're paid for and I like 'em. I don't worry about it.