What is the difference between the customer history & vehicle service history?

On the customer record there is a tab for customer contact history, which includes all the service history of vehicles they have owned or currently own, aswell as any emails/texts/order etc they've had. This data will always stay against the customer the documents were raised for and can't be transferred between customer records.

The vehicle service history which again is in the customer record but under the vehicle> history tab will move with the vehicle if it's transferred to another customer record, this tab will only show invoices raised for this specific vehicle you are in the record for.