Equations and formulas exist purely in service to concepts. If you can't tell a story about "what's really going on" (qualitatively) without reference to the equations, then (in most cases) you probably shouldn't try to use the equations, either. I see student after student try to solve complicated problems via "equation hunting", where they just dig through their notes or the textbook looking for formulas that have the right variables in them, and then look for ways of combining them to find an answer. (Sometimes their thinking is a step more sophisticated than that, but it's a characteristic pattern.) Students start to become experts in physics once their mental model of the subject transforms from a jumbled pile of independent equations into a network of concepts with equations like little neurons binding them together.