Do I need an RPA? Do I need Local Rules or an RPS?

"Do I need a RPA?" , "Do I need a RPS?" and "Do I need local rules?" are questions we are often asked. So here we provide some answers.

Atoms are very special: they like certain particular partners, certain particular directions, and so on. It is the job of physics to analyze why each one wants what it wants.

– Richard P. Feynman -