Guitar chord charts are, and have always been a great way
for a beginner to learn how to play guitar quickly. It is easy enough to
memorize a pattern and apply it to the guitar fretboard, and because of this,
most guitar teachers tell their students to follow this approach when starting
with the guitar. While there is nothing wrong with using guitar charts to learn
some chords and scales, it may be a damaging strategy in the long run if you
become too dependent on it. In order to really understand the guitar fretboard,
you need to get away from memorization and understand intervals.
Intervals are the building blocks of music. They make the scales and chords that you find on guitar charts all over the internet. The problem is that most guitar players skip right past learning about intervals and immediately go on to the chords and scales. Not only that, but guitar players rarely learn the theory behind the chords and scales. Learning the intervals will tell you all the theory you need to know about the guitar and many other instruments.
Instead of memorizing guitar chord charts, memorize charts of the guitar intervals that make up the chords. Know where all of the intervals fall in relation to the root of the chord that you are on. Once you can navigate your way around the fretboard using intervals all you need to know is the intervals that make up the chord or scale that you want to play. The advantage of this is that you don't need to memorize countless different patterns that you cannot switch around or modify on the fly. There will still be some patterns that develop in your playing but you will have more control of them and be able to modify them.
Once you know the intervals and all the notes of the guitar fretboard, you will see things come together that you would never have come across. You will be able to construct new chords and scales just based on thinking of a scale formula. Another advantage of learning the guitar by intervals is that it will be much more beneficial to your musical ear. If you have the sounds of the intervals internalized you will have no trouble letting your ear guide you around the fretboard.
Guitar chord charts and guitar scale charts can be helpful in giving you a quick start to the guitar, but in order to truly understand the instrument, you will need to be able to work with intervals.