Walmart Michaels and others are recalling Christmas lights due to risk of fire. I bought all new strings this year and just I decorate my house and took back four boxes and two spoils of lights to Walmart. They don't have any replacement ones in stock so I won't be on the light map this year.
http://healthycanadians.gc.ca/recall-alert-rappel-avis/hc-sc/2015/56070r-eng.php