Like I said, some may think about it differently than I do. All I can say is that in the last 13 years of almost continuous training that I have under my belt, the one thing I learned more than anything is ....
VARIETY.
For ME, this has become probably one of the most important elements for me to continue training WITH the INTENSITY needed to make gains.
Sure, sure, any of the training methods in the world can produce results for most people, but with out the intensity that "I" get from a variety of different methods, I just can't keep improving my physique.
The learning curve of trial and error to find what works for "YOUR" body is gruelling and long for most people. If you become lucky enough to find someone that can help direct you to shorten your learning curve time frame, then lucky you are indeed.
I've learned to keep a very open mind about the different theories out there whether it be training, drugs, nutrition... you name it.
I've tried most all of the well known or mainstream training that has been mentioned over the last ten years, and believe me, all of them have taught me something that I can use to better my physique. And some of them have even given me some memories (can you say permanant injury? unfortunately. lol) that I'll never forget. (2 years bbing, 5 yrs powerlifting, then back to bbing)
I just say read, read, read and try them all.
Only then shall you come to know oneself.
Hehehe, just thought I'd throw that in there.