I'm writing an engineering paper which is filled with equations (physical demonstrations in the theoretical section and numerical methods demonstrations in the methods section).
I want to rewrite one of the first equation I introduced, because I introduced it in a particular context and now I want to use it in another context and show different properties of it. Is this considered a bad practice?
Since all equations are numbered, there would be an equation which is numbered twice. I could solve this problem by not numbering just the second appearance of this equation. Or I could just reference the number, and let the reader go back a few pages. But that would affect the readability of the text (all the other instances in which I reference some previous equation are usually in the same paragraph, so there's no need to turn a lot of pages).
What should I do? Redundancy and readability or conciseness and elegance in spite of readability?