Of course, different areas tend to be more or less equations-heavy, but an author's individual style matters too. Two people could write up the exact same result with dramatically different number of equations. So if you observe that your papers tend to be dense with equations, it makes sense to me to try to differentiate by numbering only the ones that will be referred to regularly (my previous comment notwithstanding, because I shy away from using too many equations).
That being said, I would avoid the "above" and "below" as not artful. "Previous" is a good word, or making use of \pageref would allow you to be more precise. It's difficult to be more precise without a concrete example, but in most cases you should be able to refer to the equation by describing it. E.g. "in the long exact sequence we just established", "the previous norm inequality implies that", ...
