I have read that your body adapts, so it is a good idea to switch up your routine often. I have also read that it is best to pick a routine and stick with it.
THen some people say, "as long as your seeing results, then why change." I think that is a pretty worthless piece of advice, because obviousley if your diet etc. is sound you will see some results. I dont think it is anyones goal to get "results". I think what your goal should be is to get the best results you possibly can. I dont want to add muscle, I want to add as much muscle as I possibly can.
With that said, what is better, switching up your routine often, or sticking with a routine for a long period of time?