It’s funny I should ask this question, because I’m going to answer it myself — not for my own benefit, but for your benefit, hopefully. It’s only a short article, but it’s of crucial importance.
If you’ve done a little research already on bodybuilding you may have seen already people recommend changing routine regularly. People need to change their routine fairly regularly in bodybuilding because the central nervous system becomes too familiar with the same movements and rather than respond with building muscle from sheer shock (which we need) it begins to respond less and less, in effect capping our efforts and progress.
By changing completely, or changing subtly our movements we keep the central nervous system on its toes and vulnerable to shock. This is how we keep muscle being built week after week.
So, how often should you change your routine?
Every session? Every week? Every month? No. I advise you to change your routine only when you stop getting gains or your progress slows to a less than satisfactory speed.
Some people may not agree with this, but my logic is this: If you are making good gains as an exercise, you ride the wave and continue to milk it for as long as it produces gains. It would be foolish and pointless to change before this time.