I am guilty of this.. but being complacent or lazy and just running the State or Country is road to wasted ad spend, drill down and focus on the hot buyer Postal codes. I kept this map from a Solar group I was with some time ago, it's very revealing if you've ever just selected the whole state to run your ads because of laziness ;) even though this was part of a Solar lead gen, the leads in these areas were homeowners and that's applicable to many things such as finance, insurance, real estate, home services...etc.
Taking the time to know where your lead pools are can save you time and money later.