Do not Judge others, or do we Judge others?

I hear so much about "Do not judge others, lest you be judged." I know that there's more scripture out there that gives us a better insight into our responsibilities. Can you please answer this question. Are we allowed to judge others? Are we called to Judge others? Are there certain groups of people that we can and cannot judge? Are there prerequisites to judging others? Please start off with a simple Yes or No to the title question and then follow up by explaining the ins and outs of this confusing topic.