Importance of Major Scales
 

I just recently added major scales to my practice routine. I know how to build them and can play several of them forward and backward very well. What are the benefits that come from this?

More options in your playing seems to be the obvious benefit.

Reversing directions at intermediate points sounds helpful.

(note that I am a complete hypocrite since I know little about scales and even less about actually playing them)

The major diatonic scale is the building block and reference point of all musical terms with regard to intervals, all the other scales and modes, chords and harmony. It's the DNA of western music.
Start at the source and the rest is easier to understand...

It's like building the foundations of a great playing, also it will guide you to a better understanding of the music per se, not only the guitar. For instance, if you know scales, you'll be able of playing songs by ear.

Here is how you use your Major scale:

The director says; "The next song will be "Go kiss old Sallie" we'll do it in G and Derlan7 will take a lead break after the first chorus. Ready 1 & 2 & 3....."

From that you know that the rhythm section will use chords from the Major key of G, the vocalist will be using melody notes from the G Major scale (singing in the key of G) and when you take your lead break you will use notes from the G Major scale for the melody.

Ditto the Major scale being the foundation of everything we do, for example here are some of the things you can do with the C Major scale:

The C Major scale will use the 1, 2, 3, 4, 5, 6, 7 notes of the C major scale, i.e. C, D, E, F, G, A, B, C.
The C minor scale will use the 1, 2, b3, 4, 5, b6, b7 notes of that C major scale. i.e. C, D, Eb, F, G, Ab, Bb
The C Major pentatonic scale will use the 1, 2, 3, 5, 6 notes of the C major scale - you take it from here - that fish thing.
The C minor pentatonic scale will use the 1, b3, 4, 5, b7 notes of the C major scale.
The C Blues scale will use the 1, b3, 4, #4, 5, b7 notes of the C major scale.
The C Major chord will use the 1, 3, 5 notes of the C Major scale for it's makeup.
The Cm chord will use the 1, b3, 5 notes of the C Major scale for it's makeup.
The C7 chord will use the 1, 3, 5, b7 notes of the C major scale for it's makeup. And of course it goes on and on.....

Everything revolves around the major scale. It's the Rosetta stone for everything we do.

And of course you can play a C major scale over an A minor cord.

What are you doing with your right hand though? Are you working on all combos of right hand fingering?

Combos with the right hand? My thumb takes care of the top 3 strings, my index the third, my middle finger the 2nd, my ring the 1st. If you are asking if I move the notes around, I just play the scales forward and backward right now.

Thanks for the replies guys. Like the gentleman above said, I hope I can play by ear one of these days!

Manual dexterity.
Ingrain the different scale relationships.....helps when it comes to building chords.
Very very helpful (dare I say necessary?) for improvisation.

You learning the major scale from different positions...ie, starting at different steps of the scale and running up and back? (Getting into the different modes here) Practicing them in all 12 different keys?
This also helps you to memorize the fret board, if you say the name of the acutal notes when you play them. Even just noting the tonic in each scale helps.

resources
 

Any suggentions for the best written or internet source for fretboard diagrams and simplified exploration of major scales and their application for guitar?

I think in terms of a scale's relationship to chords. Every chord is build (or "spelled") from notes in the major scale. They are often designated with roman numerals naming the note numbr in the scale for which the chord is named.

In the key of G, we have

G major: I, G-B-D which are the 1st, 3rd, 5th notes of the G major scale. Throw in the F# (7th) and we have a G maj 7

C major: IV, C-E-G, 4th, 6th, 1st. Throw in a B (3rd) and we have a Cmaj7

D major: V, D-F#-A, 5th, 7th, 2nd. Throw in a C and we have D7. This is the dominant 7 and is muy importante in jazz and pop.

The chords built off the II, III and VI are minor chords. The VII chord is a "half diminished" or "minor 7 flat 5".

If you play the G major scale from E to E (instead of G to G), you have E minor.

It goes on and on, but this should give you something to chew on. :)