There are several advantages of having a fleet policy as opposed to insuring multiple single vehicles separately. Potentially the biggest advantage is price, once you agree the rate on the fleet any new vehicle added will benefit from the rate you have and would work out more economical than insuring a separate vehicle on its own. 

The second advantage is that in most instances, any driver that your business employs can drive on your fleet insurance without you having to update your whole policy. It gives you the flexibility to keep your business moving with minimal hassle.

There is also the administrative benefit of having one policy and one renewal date.