I don't keep trout anywhere anymore. But, there's always that chance of a fish going belly up and having to keep it. So I buy my annual trout permit for that reason along with I figure my contribution to trout funding has to help a little.Won't bother me much.
I rarely fish the parks anymore, and the last two times it was during winter C&R. I buy an annual permit every year, but I'm not sure why because I haven't kept a trout for years. I guess I get one in case I catch a giant that I want to keep for mounting.