It's common wisdom that strategic periodization is the key to rapid muscle growth, since it keeps your body guessing. Periodize too frequently and you risk churning without taking full advantage of your current training, but don't periodize enough and you risk falling into a rut.
So how long has it been since you changed your workout routine?
I'm curious because my current routine continues to deliver the best growth I've seen in 7 years of training, and I've been doing it for nearly a year now. Prior to that, I had changed routines every few months.
Obviously, if it ain't broke there's no need to fix it. Just wondering how often others change your workouts, and if the frequency may depend on the type of workout your doing.