It doesn’t take much to win a tennis match no matter how strong your opponent is.  It’s enough to win just one point, the last one.

There is an analogous saying about economics research, I heard it originally attributed to Roger Myerson.  The paper is finished as soon as you have the right notation.  This is exactly right because economic theory is about crafting the model and assumptions to highlight just the point you are trying to convey, nothing more nothing less.  There is a continual back and forth between formulating assumptions, proving results, changing the setup, checking how the results are affected, etc. until you have it just exactly perfect (Don’t get cynical now.)  How the notation is chosen, i.e. which concepts in the model get their own basic symbol and which concepts are expressed as derivatives, is a key linchpin.  By grouping the right concepts with well-chosen notation you can turn an opaque argument into one that transparently lets the main idea through, i.e. just exactly perfect.