When you've gotten used to receiving win notifications, you can easily tell the difference between a scam and a real one. I only use my regular ISP address for everything and I block any spam emails I get to cut down on them getting into my email. I don't get much spam at all. Only some of those lottery and bank security ones.
I do get alot of newsletters and advertisements, etc., that were required to receive in order to enter many sweepstakes; but that doesn't classify as spam.