Home and Garden How long do cars usually stay at a dealership? How long do cars usually stay at a dealership? Average, 90 to 120 days. Some sell within 30, others we have a year and a half later. You can see an individual cars delivery date on the invoice. Used cars show on carfax when the dealer listed it for sale. Related Posts:How do I write a basic invoice?Do CARFAX reports ever expire?How do I fix a wrong Carfax report?How does CARFAX get their information?