There is no single answer, but most vehicles in Metro Detroit do well with a simple rhythm: a full detail a few times a year and quick maintenance washes in between.
Daily drivers
A full interior and exterior detail every 3 to 4 months, plus a maintenance wash every 2 to 4 weeks. That keeps grime from building up and keeps the sealant working.
Family vehicles and pets
Kids and dogs speed things up. Plan an interior deep clean every 6 to 8 weeks, or add pet hair removal to your maintenance visits.
Work trucks and fleets
Trucks that see job sites benefit from a weekly or bi-weekly exterior wash and a monthly interior clean. Clean trucks last longer and look better to customers.
Coated vehicles
A ceramic coating does not mean no washing. It means faster, easier washing. A maintenance wash every 2 to 4 weeks keeps the coating performing.