#1
I'm kinda new to theory as in I'm using ZeGuitarist's Ultimate Guide to Guitar and I just reached the point where I can memorize about 4 out of the 7 major scale shapes but I hear everywhere that rock guitarist's don't use a lot of theory in their playing and I'm wondering if I should just be safe and vitalize all of his lessons or just certain sections because I know you need to know scales to solo and improvise but I don't see the use of chord construction for hardcore, metalcore and metal music? If somebody can explain to me how this will all tie eventually that would be great because I don't want to waste time learning stuff if I'm never going to apply it in my playing.
My Gear
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-Marshall MG10CD
-Line 6 Spider 3 15 Watt
-Jackson JS30RR
-Ibanez RG2EX1





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#2
You dont need to know theory to create songs, be it metal or some other style, but I can tell you that knowing theory will help A LOT.

I mean, if you know theory, you will be able to create cool stuff much sooner. Also its great to know wtf is going on when you hear/play something.

Gogo learn theory if you have the time and patience
#3
Theory typically will speed things up regardless of the genre, and will make explaining your song to someone else easier (believe it or not, a full tab takes a long time to make, while naming a few chords doesn't).