OOp

So I'm trying to learn OOp. I learned about all the features (inheritance, polymorphism and so on). I have two simple questions:

When is it advisable to instantiate objects instead of just using static methods? I always seem to diverge to imperative programming using only very few OOp features.

Don't OOp programs need a lot more of memory and processing power?

Thanks!

>>21
So, to, the C++ example is the best example of abstraction, not because it is the best example of abstraction, but because, in your world, C++ is the most accessible language which implements rudimentary forms of abstraction.