I give back all personal documents, photos, mail, etc., whenever I process the unit at the facility. However, If I'm paying labor by the hour to load the merchandise, I don't have time to go through the boxes efficiently and some things fall through the cracks. A unit I bought several months ago in Dallas was owned by a martial artist who was a national champion. There were 200-300 trophies in this unit. I was paying some movers by the hour so we loaded everything quickly. I left the trophies in the unit, but when I got home, I found an igloo cooler that had all of his medals inside. Although I felt bad about it, I wasn't about to drive 250 miles to take them back to the storage facility.
I know how it feels to lose a unit. I lost my storage unit when I was 25 and it had almost everything I owned it. The things I regret losing the most are my photos albums and a one eyed teddy bear that was given to me on the day I was born. Other than the obvious things like marriage certificates, diplomas and photos albums, you never really know what was sentimental to the tenant. I usually give back anything that I have a feeling is special to them, unless it's valuable. Obviously, I'm not going to give back grandpa's antique gold pocket watch, but if I see children's art work, birthday cards, etc., I make every effort to give it back.
Oh, and I too take the pictures out of the frames.