Several things stand out here. First, it doesn’t hurt to be a little overzealous with regular maintenance. Fixing issues earlier can keep them from growing into even greater problems that will balloon upkeep costs and may even keep vehicles off the road.
Second, having a dedicated maintenance team for larger fleets can save money. If a fleet is sufficiently large to keep an in-house maintenance team busy year round, it can trade the higher cost of having vehicles repaired for the lower cost of hiring skilled mechanics and technicians, and providing them with tools and some high-quality GOJO hand cleaner to clean up afterwards.