Buyers who decide within 5 minutes when doing used trades..
Characteristics of non-buyers: they only ask questions for 20-30 minutes about what they're curious about and then leave you on read...;;;
Make an appointment then cancel... are you watching, three of you...;;;
When doing used trades I answer thinking as much as possible from the buyer's side, but now if it goes past 5 minutes I start to think they're not going to buy..;;;