Fleet vehicles are bought in volume by companies, government bodies and leasing firms. They typically cover high mileage over a short life and are then disposed of together.
Fleet history is not automatically bad. Fleets usually maintain vehicles on schedule because downtime costs them money, and the records tend to be complete.
The mileage is the real consideration. Fleet vehicles are often several years young for their odometer reading, which affects wear on everything that ages with distance rather than time.
Why it matters
You are usually buying better-documented maintenance and worse wear, and the price should reflect both.
How to check it
Look at the mileage relative to age, and inspect the interior, seats and pedals, which show use that servicing does not reverse.
Does this apply to the car you are looking at?
Run the VIN or plate and see what is actually on record.
Related terms
Definitions are general guidance, not legal advice. Title rules, total loss thresholds and inspection requirements are set by each state and change over time, so confirm the position with the motor vehicle agency for the state the vehicle is titled in before relying on it.