I have been shooting professionally for 18 years (had a main street studio for the last 12),
I have always treated my gear with care probably due to the money spent. From the days of my Nikon F3's and f4's, Hasselblads, 1 series Canon film and digitals etc etc etc, nearly all my gear was sold in A++ nick. OK.... I might be a bit obsessive but I just like to look after my hard earned possessions.
During the 4 years I worked at Canon, I saw equipment come over the counter in pretty poor shape. The worst were the units operated by the press guys. Given that they did not own the gear they just chucked it around without a care. I probably would be a little less careful in their position but I reckon any camera I used on the job would look 90% better than theirs.
Anyhow, my Leicas will be well used, but I would think that the day a new owner acquires them they will most likely look pretty well mint.