My experience has shown it's best to get a dog when he/she is 8 weeks old, then you raise them as you want. I lost one to illness and have three others. Every single one from 8 weeks old. All daft as a brush and as soft as putty.I want to agree with you Lisa, all of my pets have been rescues except one taken from a friend of the family (I suppose that makes him a rescue too), but my only fear is that this then makes innocent pets taken to be sold at pet stores a death sentence if no one buys them there and that too then becomes a sort of rescue.
I would recommend rescues first because their time is most limited if not adopted, but just take a pet, any good pet, wherever you find them. The most important thing is that they just find a good home.
Getting and older dog from a rescue centre runs the risk of it having a bad side to it's character if it had been mistreated.
I don't support puppy farms, those individuals needs the shit kicked out of them.