Instrumental Technique is probably the area in which the most time is spent, and also the area where the most time is wasted. I would be the poster child for this, having spent more than my share of days practicing technique upwards of 12 hours. But if we take a moment to examine technique, there are really only 2 reasons to spend time on it.
Learning the notes:
Seems obvious, but this is something that is both crucial, and something that a lot of guitarists struggle with. This is probably easiest on the piano, the perfect visual instrument. Learning where all the notes are affords us the same possibility I touched on in part two, it eliminates any limitation on what we can attempt to play. Ideally, we should have sufficient command to play from any note to any note randomly, just like we would want to be able to hear the same. This is the one place where I think scales are a useful tool. Scales can be a good way to learn where the notes are on your instrument. But once you know where they are, stop practicing scales! The scales aren't the music, so I must really emphasize this point: only practice scales to learn where the notes are.
Executing musical phrases:
The only other time to work on technique is if you cannot execute a passage you wish to play. If you're hearing something perfectly in your head but still can't play it, then it's time to build your chops. The reason for this is simple: The goal of having any technique is to make music. "Extra" technique doesn't help us make music, so it would make more sense to spend time on acquiring another musical skill. By working on making music, you will develop most of the technique you need, and when you can't do something, you will know exactly what you need to work on to meet your musical goals. That is, you will be using your time in the most efficient manner possible. This single concept is the thing that separates elite players from the masses.
You never want to be limited by your technique, but the sole purpose of having technique is being able to say something, so be sure to spend time on your aural and rhythmic skills.
All that's left is to put it all together! Stay tuned for the fourth and final element of music!