Give them the surreptitious twist test when the salesperson isn't looking. Keep your wardrobe spotless, but don't over- clean woolen garments. Their lifespan is usually 30 cleanings. Europeans believe that if fabric doesn't touch the body, you can get by with cleaning it two or three times a year. You're lucky to get a year out of anything washable that you wear once or twice a week.
Obvious underwear is a distracting no-no.
Check for visible elastic lines under outer garments, or colored underwear showing through white pants or shirts. Dangling threads, drooping slip hems, or sagging jacket linings are unforgivable. Runs, tears and missing buttons belong at the Hobo's Ball. If your client is very casual and you're in a suit, you can still save the day. Take off your jacket, or at least unbutton it and push up the sleeves.