Batteries - every 2 years because I'm hard on them
new, check
Alternators - every 2 years
last time it gave me problems with my autoshift, so that's what I'll wait for (I still should be able to get it into a shop)
Starters - every 5 years
not that old, check
Hoses - every 5 years, or depending on condition(oil/diesel will destroy them)
I probably ought to do this. The lease purchase truck I had left me on the side of the highway
Belts - every 2 years
broke last year. I was able to make it to a shop, thank you, Jesus. check 
Transmission oil - 500,000 miles(OEM recommendation with synthetic)
Three box not so long ago, check
Gear oil - every 3 years(OEM is a lot longer then that but I'm not a fan)
Power steering oil/filter - every year (OEM)
News to me. Ok.
Air filter - once a year
On it. check
Shocks - generally every 3 years, or if they start leaking
relatively new, I check tire wear, for one. 45,000lbs of liquid, I may change them early
Air dryer - desiccant, purge valve, and heater every fall, change whole unit every 5 years
I'm not lying, I don't know what this is 
Valve set - OEM recommendations, I do it on my d12 once a year
Not so long ago, I want to find a place that'll do it for less than $400
When I do maintenance once a month, it is much more thorough then anywhere else. Of course I'm very tuned into my equipment and I know what to look for. This maintenance includes:
- Full grease job, although some items don't need grease at all(front slacks will blow seals if I grease them any more)
Speedco? 
- Removing clutch cover and inspecting pressure plate(mostly checking for broken springs), check engagement, adjustment, and clutch brake condition
I'm thinking when it starts failing, I'll still be able to get to a shop
- Full brake inspection, brake stroke, wheel seal leaks(oil on drum), check for broken parking springs in brake chambers, make sure the slacks are adjusting properly
company mandatory quarterly inspection!?
- Remove top plugs in diffs and clean. Check oil level, and quickly swap with bottom plugs(to prevent oil draining). Check/clean bottom plugs reinstall on top
Speedco!
- Check belts and alignment, all hoses, every inch of exhaust system
reminds me, I want to get a freeflow muffler. Exhaust pipe is new from muffler to the flex coming off the engine.
- Check battery terminals for corrosion and looseness
Yeah, I keep meaning to clean my terminals. A corroded wire at my cut off switch cost me a late delivery. Thankfully, I was at a TA that night. Since then, all the those connectors have been replaced.
- Check alignment(toe in)
I just pay attention to any pull and respond accordingly. check, I hope.
- Check front wheel bearings/oil
Mine are sealed
- Check for air leaks,
spray air bags and fittings with soapy water
Probably not in this lifetime.
Whenever I replace or repair something, I always try to improve the design and/or prevent corrosion. One of my favorites is stainless steel bolts. Quick disconnect air fittings are a PITA, I always try to change them out with compression fittings. They always leak.
Some examples of improving are putting in better batteries, gear reduction starters(39mt or denso), delco-remy 35si, 36si, or 40si alternators, oil bypass filters, extended life oil filters, haldex lifeseal brake chambers, red coolant, synthetic oils, magnets to catch iron, compression fittings, stainless steel(bolts/hardware/brackets) on and on....
Maybe I should have one of those Visi-checks done. You know, the vibration. Opinion?
I also have a lot of spare parts. Hoses, belts, filters, purge valve, air fittings, air lines, alternator, fuses, lights, relays, breakers, wiring, fluids, and LOTS of tools.
Plenty of duct tape. check.
Wear items that are high $ suchs as kingpins(looseness), springs(looseness, clunking), clutches(rattling/clanging), bushings(cracking and falling apart), motor mounts(cracking, falling apart), CAC(test with CAC kit), radiator(leaking), turbo(whining), air compressor etc... are changed on "it needs changed" basis. Usually you can catch this kind of stuff before it goes.
Groovy U-joints should last a long time if the drive line alignment is correct and they're greased properly(some only need every 300,000 miles, do it before that you're actually hurting them).
Other things that you can do include oil analysis, and many engines have some sort of diagnostics. For example most engines you can do an "idle injector test" that tests how much each cylinder is contributing. Dyno/blowby tests can reveal problems as well. Manual compression tests as well.
oil analysis, check.
Simply rebuilding your truck as new and expecting it to last forever is a recipe for disaster. You need to learn what your truck needs! Even brand new trucks need maintenance within the first year.