Everyday of your life, you might create dozens of class into your image. While doing it, it is often the case that you make mistakes writing #hash, #= to your class. #hash and #= are very close to each other, but a slightest mistake can cause hard to find bug. Any two object of equal must yield same hash value.
Make a method that creates EqualityComparison object and supply the 'getter accessors' to it and implement both #hash and #= by using the object. It is simple, time saving, and foolproof way to go.