Scales are learning tools. After you get good enough, you won't even need them! (they become cemented in your brain, and after a while, you'll understand how each tone and semi-tone reacts with each other, and this is when you first 'see' the music. I've 'seen' the music twice so far, one time at my former guitar teacher's house, and one time while jamming with my band during one of my 35 minute solos (I'm a lead guitarist in a Jam Band).

It's a rare phenomenon, but I think that every serious guitar player has had it happen at least once, usually it goes so fast that you don't even see it. One way i can describe it is when you lose control of your subconscience, you are no longer playing music, the music is playing you...

If you don't understand what that means, think about a time when you record something, and afterwards, you say to yourself "man, how did i record that???" or "was that what i was playing???"; That is when you lose all judgement....you just play, you know?

Back to the subject-

Don't learn the 4 notes per string or 3 or 5, learn all the notes per string, per scale; there's no reason to limit yourself.

~Incidents