Science is useful because it has the power to predict. It gains this power from getting the same output when providing the same input. If what you are doing doesn't have the power to predict it's not science. You can still apply the scientific method to what you are doing and if you're applying that method you might as well call yourself a scientist and what your doing science, but then again, a few hundred years ago scientists didn't yet know that things like alchemy weren't science, so they applied the scientific method to it and figured out that it isn't useful.