What Kodiak said covers it very well.
I consider myself a novice , at best.
But dedicated.
If you can see them, they are edible to me, until they become old and tough.
Never too young (actually prefer them that way).
In the 3 years of record keeping , it appears to be about 65-70% reoccurrence.
Have pictures of them in the same exact nooks at the tree base.
Dates are within 7-14 days each year so far.
You are harvesting the "fruit" of the mycelium (root system) of the mushroom.
The tree is their host, and the mushroom stays until it dies (sometimes many years).
During the peak of the growing conditions here , I was checking every 3-4 days.
As I found a weekly check to produce many that I felt were very edible ,but beyond my preference .
I found the best tool for me, was to digest some online info on growing these at home or commercially.
Some sites go into great detail on perfecting the conditions for maximum yields.
Helped me keep the percentages up, I felt.
I found my best results with short term (8-10 day) storage to be a lightly dampened cloth covering and refrigerate.
Long term to be frozen , pickled, or dried.
( small chunks of dried ones into a pepper grinder to dust the tops of steaks , ect.)
I have gotten pretty long winded here but hope this can be of some help too you.
Growing Maitake Mushrooms