How do I know if mushrooms have gone bad?

I bought 1/4 ounce of psychedelic mushrooms 2 months ago and never ate them. They are not in a humidor or even an airtight container for that matter. They are sitting in a bag tightly wrapped up.

I was planning on eating them soon but I was not sure if this was a bad idea. Does anyone have any idea what the life expectancy is?

I figure the worst that will happen is that they will have no effect on me or make my stomach ill but I’m not a big mushroom eater this will only be the 3rd time I’ve eaten them. They are dried so I figure that should allow them to last a while but they have definitely gotten harder since I bought them. How long do I have??