Not Being Judgmental

When is sound judgment acceptable and when does it cross the line into being judgmental? There are those who use the words “judge not lest ye be judged” as a basis for rejecting any criticism of whatever they want to do - no matter how depraved. Well, those words of Christ from the Sermon on the Mount were obviously not intended as a free pass to a sinful lifestyle. So, what did Jesus mean when He said in Matthew Seven, verse one “Judge not, lest ye be judged”?