I believe each person you talk to will give you different reasons as to why they're self taught or took lessons. I picked up a guitar, tried like hell to teach myself for about a month, playing every day for about 3 hours and learned about 10 songs. By luck, a guy came up to me while we were having a garage sale and asked if I had any guitars for sale. I told him "not yet, but check back in 6 months". We got to talking and he ended up offering me a free lesson. That lesson lasted 2.5 hours. I've taken about 10 more from him since then. Each lesson costs me $25 and isn't kept to any certain length, but the shortest one was still over an hour and a half. The guy doesn't even really need the money, he teaches because he loves the guitar. I've learned so much more from him than I could ever have learned on my own. He helps me learn "why" I'm doing things rather than just learning chords/riffs. It also helps to know exactly which fingers are supposed to be on what frets down the road, when you're trying to shred but can't figure out why your pinky can't get down to that last fret with ease. Practice doesn't make perfect... perfect practice makes perfect.