When is it okay to judge someone?

When is it okay to judge someone? The simple answer for a Christian is never. But we all do it. For instance, a few days ago I wanted to add Ralph Klein to my Facebook list of influential people. However, I found I could not because I disagree so strongly with drinking and driving and he was a drunk. However, Churchill (a notorious drunk) was on my list; but, 70 years ago drinking and driving was socially acceptable (or at least overlooked). So, does that make it okay? Well, no; but, because of how society viewed it, Churchill was not really any worse for wear. Plus, I've always made the distinction of judging my man's standards vs. judging by God's standards. That is to say, I never judge a person as being worthy of going to hell, although I can't add Ralph Klein to my Facebook list because his behaviour is socially unacceptable.