Liability?? Sounds like a good reason to not do stuff.
You should not be doing stupid stuff, or billing your self as a Master Mechanic without a ticket, but helping a buddy or someone new to the hobby with some basics maintenance is a good way to make friends and grow the hobby.
How many problems, time and money could a guy save if someone showed him how to use a torque wrench, and to check wheel lugs or nuts and bolts before, during( daily pretrip) and after an overland trip?
You don't need 20 to 50 thousand dollars in tools, but you should have a decent setup. A 290 piece socket set, small Impact socket set and Impact gun, with a good selection of Wrenches. Total of two tool boxes, a socket case and an Impact gun, you can adjust, replace or install 80 to 90% of the parts on the vehicle. Need to do ball joints/Delta joints/Uni-balls, and tie-rods? A front end service kit only runs about $100 CDN, and makes changing a bent tie-rod on the trails way easier. Yes after I replace parts on the front end, I'll take it into the shop for an Aliment, cause I don't need a 15 to 30 thousand dollar machine that only gets use once or twice a year.
Billiebob says "Can I change oil, sure but if I let the shop change the oil they also check the driveline, steering, lighting, brakes.... for under $100. so why change the oil at home."
As for just letting the shop change oil, so they can tell me if my light are not working, or my brakes steering or driveline is "OK", Maybe you need to get your face out of the phone and check things like your lights about once a week yourself. Does your steering wheel feel funny, are your brakes not working as well as you like? Does your Steering shaft or driveline have too much lash( play) ? You should know if something needs to be looked at before the shop tells you. Well I may sound harsh about it, you as the driver are 100% responsible for insuring that the vehicle is safe to drive on public roads. Get pulled over on the way to have the oil changed so they can tell you that a light does not work will still cost you a ticket.
As for Oil changes only costing a $100+ for the shop to do, yup sounds right. Thing is my oil is going to cost me about $80, plus $40 for a filter. So why give the shop $100 to 150 on top of the cost of parts? I can drive to the store, come home let wife put stuff in the fridge and I drain the oil. Well I am under the truck, I can give my drivelines a twist and check the lash, check the torque on nuts and bolts etc. A nice relaxing couple hours working on the truck and talking to my neighbors. The money I DID NOT give to a shop is enough to pay for my next OIL change, or a tank of gas for a trip.
I should touch on the Liability thing in a more serious note. If I have to worry about Liability, there is a pretty good chance you are going to stay stuck, no recovery attempts because of liability. Need a ride? sorry Liability. Your Air compressor broke and you want to borrow mine to air up for the Highway. Sorry Liability.......Yes it sounds stupid, but 'Liability" is a real catch 22.
Think of it this way. I come across you stuck on a logging road or a trail. I can't attempt a recovery because of Liability, I can't give you a ride to town because of Liability, I also CAN NOT leave you stranded because of LIABILITY. How much Liability do I have to except and How much PERSONAL RESPONSIBILITY are you going to take if your vehicle or gear gets damaged in a recovery, or you spill a hot coffee on yourself well your riding in my truck?