Because you should have known the answer to your own question really .
Private ; un loved filthy cars , scratches on paint , stained seats , missing bits , bald tyre , wheel scuffs , missing key , short MOT , needs Service , and fumigating .
How do i know this , because we get PX cars from privates and i haven't seen a good one in ten years .
Dealer ; Polished , prepped inside , seats carpets cleaned , Mats replaced , Serviced , Wheel scrapes repaired , warranted , New MOT , two keys , No obnoxious smells .
This Asif is called a JOB and done correctly it provides a great service supplying cars that people can buy and enjoy owning .
So moral of this is .
Private is a risk and unless your good at mechanics , deep cleaning cars , and traveling the country looking at scrap sold by liars , USE a garage instead .
Now that's not cocky is it , just true