I know this is an old thread, but I just wanted to concur with something mentioned above... I've seen folks who are relatively new to wild mushrooms, and a few who claim they're experienced, correctly identify them, but then pick and eat mushrooms past their prime and/or badly infested with bugs and their feces. In some mushrooms it isnt real obvious unless one knows what to look for. Can this be a reason for some upset stomachs? Perhaps. I've hauled too many mushrooms home myself that I've thrown over the hill when I got to cleaning and closely inspecting them. I try to be more selective in the woods nowadays just to reduce that unnecessary work.
Aside from visual inslection, I always give sheepshead/Maitake the sniff test. They should smell like nothing, or lightly like clean fresh dirt, leaves, etc. Their odor changes when they pass their prime and begin to sour until they smell pungent and eventually like an old pair of stinky gym shoes. Lol. But anything besides fresh, and I let them right where they are... or maybe scatter them around other nearby oak trees.
Found my first Maitake of the year yesterday.