i have an old 1972 AirCo "Dipstick" [name fits me perfectly. ] mig, tig, stick welder i bought back in 1996. it's 200 amps on tig and stick, and something above 160 on mig. [the adjustment crank goes about 1/2" above the 160 amp mark]
it has either .030 or .035 wire in it all the time, and the only service i have done is replace the liner twice, and the usual tips and gun barrels.
that thing is HUGE, and is on wheels. it has a lifting ring on the top, and it took my engine crane to unload it.
i have a new tig torch setup still in the box i have been going to try for years now, but i never get around to it.
for exhaust work or body panels, i have a century 110v that has .023 wire in it.
for big stuff, i have a 1970 lincoln "tombstone" i bought new. there has been many 6010, 6011, 7018, jet rod, and others burnt through that thing over the years, and i'm glad i kept it all this time. i have had to do nothing to it service wise.
my one peeve is guys throwing an arc on the ground clamp before they start. why do guys do that ? that sure dicks up the clamp !
if i need to do a test, i have lots of scrap to use for that. boneheads !

for a lid, i started out with an HTP Stryker. that thing worked great for many years, but as my old eyeballs got some mileage on them, i bought a lid [i can't remember the name or model] that had a JUMBO viewing screen. that is larger than the common BIG screen. it also has a knob on the outside left side that can fine tune the lens color number.

if i need extra light to see the weld joint when using the mig, i tape on one of those small, round Hobo Fright "freeby" flashlights to the mig torch.