Average when it comes to fluid changes (oil to diff fluid and anything in between) as well as tune ups (plugs, wires, dist. cap & rotor) plus whatever category my resume puts me in when it came to my own maintenance beyond that. In order of car owned:
1975 Nova - took out the engine and interior once I snapped a second flywheel
1998 Dodge Dakota (dads truck) - Fuel pump was about the only major thing I did beside replace a water pump. He let a mechanic handle most of the work that thing needed.
1996 Dodge ram - ball joints, upper intake plenum plate, timing chain, water pump, dash replacement, speaker install, headliner replacement
1998 Jeep Grand Cherokee already lifted 6.5" - replaced shocks, Currielync steering upgrade, rewired sound system (speakers, amp, head unit)
1990 Nissan 300ZX - A LOT! bigger brake upgrade, 120K timing kit 3x (various reasons), fuel injectors, gaskets, suspension (Coilovers, control arms, tension rods, bushings), rear main seal, ptu relocated, fuel pressure/oil pressure/voltmeter/water temp gauge install. Probably more, I've nearly taken this car to bare bones and have reinstalled several things but a lot more to do.
1996 Jeep Grand Cherokee LEMON - rebuilt the front end with all new parts, tie rods, ball joints, the works. Also did timing chain and intake plenum plate. Lot of work on that thing for nothing, it had way too many issues to keep.
2009 Matrix - spark plugs? Haven't really done much beside fluids since Toyota makes a fantastic daily driver
1998 Jeep Grand Cherokee 5.9 - 2" lift kit coils & shocks, balljoints, outer tie rod, rewired speakers with a new aftermarket amp, timing chain, water pump, intake manifold gaskets
2002 Infiniti G20 - replaced the engine with a JDM engine, replaced all the seals/gaskets beside the oil pan gasket, shocks, new aftermarket sound system (wiring, head unit, amp)
Nice trip down memory lane haha
I've learned a lot, broke a lot, and know I have much more to learn. Actually starting a General Service Tech job soon.
Edit: My reasoning for considering myself average is all things I've done I didn't have to go to school for. YouTube, FSM's, forums and common sense make a lot of things possible. Oh, time and money too of course! I would consider a mechanic who has a shop with above-average tools, specifically diagnostic equipment, to be in line to be considered a professional.