1. Don't answer if you don't recognize the number (your parents taught you not to speak to strangers, right?). You won't hurt their feelings – they have no feelings; they just want your money, credit cards, personal info. In other words they want to ruin your life.
2. Don't call them back - don't assume they'll put you on their "do not call" list. They won't even if they say they will.
3. Don't complain about the number of times they call if you don't use your own (your service's) Block Caller list.
4. Be proactive and responsible by using your own protection. Assume nothing.
5. Get on your phone service's Blocked Caller list - if they don't have one, get one that does. If there's a fee, it's still worth using it for your peace of mind.
6. Don't think the government's Do Not Call list is going to handle it - they won't.
7. Google the number.
8. Add the number to your personal Block Caller list.
9. Get on with your life – you don't need to answer every phone call.