I break most of the MOC down after building or if my kids play with it, after it's survived few weeks. Sometimes I keep a part, I've kept a stagecoach from my western MOC and part if a dragon from another but mostly the piece get recycled.
I do take a lot of photos during construction. Mostly because accidents happen. Twice I've had things knocked off the table! Or I change something and decide I don't like it as much as it was an hour before.
I'll post odd pictures in my Flickr feed if someone asks hey how did you do this or that part. But generally those construction photos gather dust.