Any job, like any relationship, has its difficult moments. With the job market heating up, the temptations to change partners are growing. As with any relationship, however, you really should <A HREF="http://money.cnn.com/2006/05/31/commentary/everyday/sahadi/index.htm">assess the full value of what you've got</A> before giving it up wholesale. Workplace experts Marcus Buckingham and Curt Coffman have identified several criteria in their book "First, Break All the Rules: What the World's Greatest Managers Do Differently" you can use to measure whether your job is worth keeping or not, offering a useful guide in the form of 12 questions.