It is always important to test. Especially in planted aquariums to make sure your parameters and coral nutrition are in check to help skeletal/flesh growth and prevent algae outbreaks.
Kh, Ca, Mg, NO3 & PO4 are allimportant for coral growth and system balance.Testing is also convenient if something were to go wrong. You have test kits ready to check what could be the culprit leading to your issues.
Aquarium Gallery also offers in-store testing! To help you fine tune your aquarium and provide steps on improving.