I never answer calls if I don't recognize the number - too many shysters calling with temporary 'phony' phone numbers.   They change their number more often then we change our underwear so as not to be 'tracked' by the FCC.

A note on Unwanted Calls.  Our world is changing. Sadly - The 'Do Not Call' list only works with Legitimate Telemarketers but unfortunately does not apply to: Surveys, Charities and of course, Criminals don't follow any laws. These Criminals have various kinds of ploys.  Some hide behind Surveys and Charities and of course the two big ones are Phony Debt Collectors and Low Interest offers.The only way to avoid these calls is DO NOT EVER RESPOND because if you do respond you will not only continue to be harassed by the same caller but your number will be sold to other 'Harassers' now that they know you are a live Human Being with a real phone number.  Also the Criminals/Shysters only use a number for a short period and then change it to avoid being caught.  Another sad note is that even if you do respond to a legitimate Survey or Charity - you will be placed on a 'Sucker List' and your number will be passed To & Fro for all to exploit you, including the criminals.  I also never respond to any political calls anymore, because I don't want to give any politician the knowledge of my concerns just so He/She can LIE TO ME in the future by telling me 'What I want to hear', because - Honest Politicians already 'know' the Needs and Concerns of The People that He/She is representing.  Again, our world has changed and responding to any of these callers only places us at risk for 'Who knows what?" At this time in history I have not discovered a way to 'AVOID' ALL HARASSMENT and so far the only way to avoid ongoing harassment is -Caller ID- and/or a phone that can 'Block' callers who will not stop.  Some of these phones also have a Programming Feature that will BLOCK Calls which do not have a number like 'Out Of Area' or 'Private Caller" and is well worth the Investment.  We can no longer 'Trust' ANYONE "Who we don't know' that is calling us.