A variety is absolutely essential to the well being and healthy growth of your dragon. I always used Rep-Cal for more of a supplement than I did the main diet. I feed my Dragons live crickets, mealworms, greens and then some Rep-Cal sprinkled on top of the greens. My crickets also get dusted with Calci-Powder to ensure their calcium levels remain at safe levels for them. All of my Dragons are in excellent health and are comparable in size.
I have also talked with Dragon owners who fed Rep-Cal exclusively and they had issues with their pets becoming impacted over time. Not sure if feeding their pet Rep-Cal exclusively was the culprit, but I've seen nothing to say it couldn't have been the culprit.