You can change the gear oil every week, but gear teeth, and bearings still degrade from heat, and wear. Usually the silent chain in the transfer case gets noisy around 250k miles.
Its fun, more in tuned with the truck, more control, CHEAPER to buy, no "learning process" like the automated trannies, rare, fun, far less chance of being stolen, fun, rare, cheaper to buy, doesn't shift at the wrong time or place, no constant gear hunting and fun.
Course not....did you ever ask them to? Doesn't matter whether you use 4wd or not...how do you think power gets transmitted to your rear driveshaft?aint no yota mechanic nor slopshop has ever advised me to take a look at that transfer case
i don't often get to use the 4wd much anymore because it does not snow much around here other than every 3 years now