it's just like most guys who run a saw 40 hours a week think they're actually *running* the saw 40 hours a week. Put an hour meter on that saw and they're very surprised that it's only an hour or maybe 2 each day. Same deal with welding (ex contract welder here by the way). If you're a welder fabricator then you could see as little as 30 min to an hour a day of actual trigger time. Even if you work in a best case high production environment where somebody else is prepping your stuff, you still need time to layup and tack the parts, check alignment, go to the toilet, have lunch, change wire, adjust your welder, change gas, scratch your ass, get some information about the job, move the part to and from your work place etc etc... the amount of time you actually spend with the helmet down welding is a lot less than what you might think. Worst job I ever had was 12 hour shifts repairing copper pots in the mines. The pots were about 20T, and you sat inside them. They were preheated, and we were building them back up to tolerance where they had worn thin, usually they were 6"~10" thick with a layer of hard facing on top. We were welding with 25kg rolls of 3.2mm wire and we'd put 3 or 4 of those rolls into a pot in a shift. Even in that job, there was a fair amount of 'non welding' time due to having to arc air gouge the hardfacing off, grind the surface, weld, then chip the slag (it was dual shield), clean it up, then lay another pad. But one pad could take 15~20min of continuous welding. That was then followed by chip, cleanup, another pad. There aren't many welding scenarios like that, but even in that environment I'd be surprised if trigger time accounted for as much as 40~50% of the day.
You can tell a lot about your trigger time from your consumable use be it tig, mig or stick. You'd have to be going through 7 or 8 15kg rolls of mig wire a day if you were welding non stop 6 hrs a day, and maybe 2 or 2 bottles of gas. Same deal with TIG, I'd think a conservative estimate would see you going through 4kg or 5kg of filler a day, which is what a lot of guys use in a week. Or 8 or 10 packs of rods on stick.
Shaun