Appearances

I have been listening to Christian radio lately. One thing really struck me. About 75% of the ads have to do with appearances. There are wrinkle cures, hair removal, baldness cures, weight loss commercials, etc. This got me thinking. Just how much should Christians be concerned about their appearance? I understand that people often judge us by our appearance. But how much should Christians care what others think? Now I am not advocating just letting yourself go and being as disgusting as possible. But when do fashion and outward beauty become idols or stumbling blocks?