When importing Customer and Vehicle data from a system, generally the database being imported is not "clean" and contains a lot of old, obsolete or incomplete records.
Fortunately, there are often some easy ways of cleansing the data as it's imported and on an ongoing basis.
Providing Service History is being supplied it is possible to age vehicle records based on date last seen. Vehicles can then be flagged for archive or to be set for no service follow up based on this date.
Experience suggests that for many dealers archiving based on 5 years since last Workshop Visit and stopping Service Reminders after 3 years works well. The exception to this is for vehicles with longer manufacturer warranties, where it may be logical to extend the archive period.
Navigator can bulk lookup vehicles against the DVLA V5 database to gain correctly structured vehicle descriptions (which makes marketing selections more consistent), chassis, engine nos and registration dates. There is a charge (5p per record) for doing this. It is normal to do this for vehicle records that have been seen in the past 3 years to make this cost effective (£50 per 1,000 records).