I practice all the scales. Everyone should know lots of scales. Actually, I feel there are only scales. What is a chord, if not the notes of a scale hooked together? There are several reasons for learning scales: one, the knowledge will unlock the neck for you — you'll learn the instrument; second, if I say I want you to improvise ofer Gmaj7+5, then go to Eaug9-5, then to bmaj7-5 —well, if you don't know, what those chords are in scale terms, you're lost. It's not all that difficult, but you have to be ready to apply yourself...

Denyer, Ralph (2002). The Guitar Handbook. p. 114. ISBN 0-679-74275-1.