It's been some time since i posted on this topic....but i figured most wouldn't agree with my logic. First off, I only recommend this proactive preventive maintenance approach to a select few of my customers. These select few practively live in their cars & they put well above the 15,000 yearly average. I really think that stressing about mileage is overrated anyways, i would love to see a engine hours gauge instead for a barometer for maintenance. In Chicago traffic it can take you twenty minutes to travel just one mile. That whole time fuel pumps, alternators etc. are turning the whole time.
We change engine oil without sending a sample to the lab for analysis....alot of us recommend battery replacement after 3 years, even if it seems fine at the time. Theres alot of services or replacement we recommend based just on time or mileage...I just use this approach to the few customers that cant afford the inconvenience of a breakdown like couriers, deliverymen, salesmen and such. These guys are usually on top of their maintenance.
Since onsite breakdown work is my niche...i see the results of neglected maintenance quite often. I don't see the harm in being proactive as long as the customer understands they are in control when the vehicle is out of service, and they are totally within their right if they choose to wait till it fails. I just give them the option of having more control of down time of their vehicle & they are able to budget for it as well.