i wouldn't create a base class until there are a non-trivial amount of common properties shared by several classes and i find that i am adding more such common

i wouldn't create a base class until there are a non-trivial amount of common properties shared by several classes and i find that i am adding more such common properties. and when a class appears that doesn't have one of these common properties, then perhaps it makes more sense to move that one no-longer-common property out of the base class back into the individual classes so that again i can have all classes share the same base class.