Rant: a wedding photog in Tulsa handed me a Zorki with sand in the shutter and laughed
Spent 2 hours flushing grit out with lighter fluid while he told me the couple's dog ate the lens cap mid-ceremony. Now I do a full dry-fire check on every walk-in before I quote a price, so what's your go-to test for sandy shutters?
Same thing happens with used cars, people hide the problem until after you paid. I always pop the hood and check the oil before I even talk numbers. Trust gets you nowhere, a quick test saves you a whole afternoon of scrubbing grit.