Photon get tired? Can't imagine how that would work. Law of conservation of energy. We have some very old photons to investigate in the form of cosmic background radiation (Penzias and Wilson). Nobody's reported anything hinky about them as far as I know. Now there's your red shift - all the way to microwaves.


The key elements in human thinking are not numbers but labels of fuzzy sets. -- L. Zadeh

Which explains a lot.