Why should you change employers?
The reasons why cooks switch often.
Moving to a new job or travelling
When making a move a cook also wants to consider that they should be looking for an upgrade in responsibilities and work their ways up from chefs de partie to junior sous chef to executive sous chefs and so on. That the idea of working anywhere really you always want to move forward. At this point in time cooks are trying to make names for themselves and potentially soon take that next step, to a cook a better job offer a whole new skill set and whole new experience.
Eventually most cooks who stay at it for this long will have the opportunity to chef in a restaurant and possibly even own their own which in turn means you can finally relax a bit and let the cooks do the work your way, doesn't that sound great? This is also however a whole other level of learned experiences and knowledge,