I have 2 cats; one of them seems to get tired of one when I give it out for more than a week or so. They in airtight storage. So I'll open a new packge and she may eat them, but some days skips them altogether. I'll have to see if his hot wether makes a difference or if it's a specific flavor.
He only likes hard treats, and the company that made the ones he used to eat quit making them. The Greenies are just as effective, I think, and he likes them as much as the old ones. I've recommended our local VET begin ordering them and keep them in stock.