In managing CompanyEmployeeRelationships, it makes sense to follow ThePrincipleOfPerceivedValue.  This applies primarily from the employees perspective, although as we fill out this Wiki page I welcome alternate Company-based perspectives!

In principle, you are hired for certain functions that you agree to perform for a mutually agreeable remuneration.  In reality though, time and progress change your relationship.  After a while you need to step back and ask yourself if your employer has the capabilities to truly perceive the value that you can offer.  If you feel that what you can offer is beyond what they would perceive as your value, then it might be time to seek a new employer who has that capability.