There are times when it is a good idea to change your exercise routine, for example if it has stopped producing results, your schedule no longer allows you to follow the same protocol, you are having issues with injury, etc. However there are also times when it is not necessarily a good idea to change your routine, I look at it like this, if it’s not broken, don’t fix it. I see people all the time that are changing their workouts too frequently, you have to give a given split or routine enough time to see if it works for you. I am not saying you should stick with if for 6 months but a good time period to reevaluate is around the 4 week period. This amount of time should allow you to ascertain whether or not the new program is producing results. So if it’s not broken, don’t fix it, and if is it, well then fix it already!