"How To" answers to 3 questions about difficult accounts

How do we handle an unethical customer?  One who says he would do anything to make money on a job, or to get a job?                             

Dave, how can a sales person have a life at night and not be reactive to customers calling at night – seven or eight per night?

In regards to personality conflicts with an account, at what point do you walk away and let someone else in your organization try?