But you dont
Give each and every car a fresh mot at point of sale by an independent mot station so no mates rules
Sort out any issues so car has no advisories for customers or trading standards to nit pick on unless obviously it's something like slight corrosion to brake hose ferrules or slight corrosion to front subframe, you wouldn't change these items but you would underseal or protect them
Have each and every car go through a comprehensive tick box pre delivery inspection
Have each and every car go on a 10 mile drive to confirm no problems
Do all this and you cut problems down by 99%
If you do then get a visit by trading standards or heaven forbid you go to the small claims court you can prove you did everything possible to sell a proper sorted car prior to sale and this goes in your favour because it shows you keep records and show due diligence to the trade we are in
Remember everyone loves us as they buy a car today but tomorrow if they even hear as much as a squeek tomorrow you are their enemy
Finally always keep business and pleasure separate if you like a nice quiet pint