When to Change Your Routine
To maintain steady progress, I recommend taking a week off every 2-3 months, as this will allow your body to rest from any overtraining. Also, consider changing an aspect of your routine every 2-3 months (however, if it is working well, don't change it) - a good time for this is right after a rest week. This change could involve your rep range, number of sets, rep scheme, exercises, and/or split.