Believe it or not, I learned MIG about two years ago from watching as many YouTube videos as I could. Went out and bought a used Century MIG at a pawn shop, sales guy threw in some gloves, a chipping hammer and a cheap hood, so I rushed home looking for any possible piece of metal to practice on. I'd sputter and spark, run inside and scan the welding forums and welding videos, then run back to the garage and go at it again. I eventually added argon and got the hang of it. Then I spent some time in my father in law's shop and played with his 220 Volt MillerMatic MIG. WOW! What a smooth buzz compared to my 110! Three weeks ago I started watchin stick weld videos on YouTube and I bought a small 70 amp welder on sale at Northern Tool for $69.00. I picked it up rather quickly, but the low amperage left a lot to be desired. So back to the FIL's shop... Two days of stick welding with the Miller Bobcat and I'm quite impressed. One of his workers taught me a few tricks about forming the puddle and such. That helped a lot!
But to answer your question; I guess I'll always be learning to weld. I'm never really satisfied with my beads; especially after I see the "stacked dimes" here and on other welding sites. I'm starting to watch a lot of Oxy/Acet videos now...