What is the rule of thumb about replacing knob and tube wiring in an old home?I have heard from electricians either to get it all out or don't worry-just replace when a wall is open. Any old home buffs-professional or not-out there who have battled with this question? What was your outcome? Need advice before the addition starts!! June 24 2009 - US00YesReport a ProblemProblemSelect oneOffensive contentIrrelevant contentSpam (pure self-promotion)OtherDetailsYour emailPlease enter a valid email address.Submit CancelContent flaggedWe will review this content. Thanks for helping make the site more useful to everyone. To learn more, read Zillow's Good Neighbor Policy.We're sorry. This service is temporarily unavailable. Please come back later and try again.