Expiration

Is there an expiration date for jobs, and if not, should there be? More and more I find myself feeling unhappy if not ill at ease where I used to be so very, very happy for a long time. Almost 8 years ago I got hired as a substitute and from the start I knew this was the place for me. During those years I got promoted from sub to one day a week employee to part timer doing 22 hours. I loved every minute and ever change was accepted with open arms. Those days seem long gone. Being part of the workers council gave me a look behind closed doors, that I’d rather not have seen. Little irritations are starting to become obsessions and I feel myself getting pulled deeper and deeper into a feeling of discontent.
Time to put my resume out there and move on?