I'll use myself as an example. I wheel at least 2-3 times a month, and the rest of the time, it's a daily driver.
I do all my own servicing, with the exception of lube/oil/filter - which a local nearby quickie lube does for me roughly at the cost of me buying the oil at a local auto shop.
So, here's my actual schedules:
A Service - Every 3000 miles - Lube/Oil/Filter. My time, 30 minutes waiting for the quickie lube guys
Before and after every off road trip - Lube every Zerk fitting. Total time, 20 minutes
B Service - 2 to 3 hours, it's every 6000 miles. Includes the A Service at the quickie lube.
C Service - Every 12000 miles. Includes A and B, and is more detailed of an inspection. Give it about 4-6 hours depending on what I need to fix.
Unexpected fixes - I have had four in the past two years - Vacuum pump, Head gasket, glow plugs, and power steering gear. Vacuum pump - 4-6 hours. Head Gasket, two people at 8 hours. Glow Plugs - 2 hours (by myself), PS Gear - just happened. Give it about 6 hours by myself if it's not a hose. If it's a hose, 20 minutes.
So - I spend about 3-4 hours a month, averaged over 1 year.
I can definitely say that I have kept the repair needs at bay due to the Severe Duty cycle service. It's effectively halving the lube jobs, or in my case, I lube the truck before and after each run. My idler and pitman arms are still the original upgraded Moog parts that were installed when I first got the truck 2 years ago.
Want to look at what's involved? Check out this site:
http://www.amghummer.com/Maintenance...duledMaint.htm