>>It goes without saying that (1) only the class definition is kept in memory (2) the object properties are not shared. Properties have to be initialized each time
>
>I agree. I thought so too as property values are different (or could be different) for all instances of the class.

But then it's only properties with nondefault values. The rest are looked up in the class definition (or parent class, if at default) when needed.

(Of course, I do not really know this; I think I read it somewhere once upon a time, or more than once,but can't remember where)