On the topic of spending and inordinate amount of time on things - I definitely spent far too many hours trying to play that those 2-octave major scales at crazy fast tempos - like Al Dimeola would (he's actually a topic for a different thread - loved him at first, then as I learned more about music and listened more, began to really NOT be impressed with many of his compositions. But I have to thank him for introducing me to Paco de Lucia, who I really continue to enjoy and be inspired by.)

But back to the warmups - I can see what you are saying maybe being adequate for electric guitar, but more demanding acoustic playing can be quite physically demanding - both steel or nylon string. Let's see where others weigh in on this one.