I have an electronic version of the shop manual for my Nissan Xterra. It weighs in at a fairly hefty 2,720 pages. The top three chapters, page-count wise are:
Engine Control System - 1198 pages Automatic Transmission - 342 pages Electrical System - 268 pages
Fortunately, at 67k miles, all I've had to do is change fluids, battery, brake pads, tires and a rogue power window switch panel.
The most esoteric part of the vehicle, thusfar, has been trying to find GL-4 gear lube for the manual tranny. Otherwise, it's a pretty simple solid axle body-on-frame truck chassis with nothing really odd-ball like side curtain airbags, HID lighting and so forth. Knock on wood it'll be reliable for many more tens (or hopefully hundreds) of thousands of miles. I can't imagine owning some high-dollar SUV like a Lexus, Escalade, Denali or the like.