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!

>>22
Let me see if this helps.
Best DE-FACTO example [of abstraction
Best DE-FACTO example [of abstraction
Best DE-FACTO example [of abstraction
Best DE-FACTO example [of abstraction
Best DE-FACTO example [of abstraction