can you tell how long a leaf has been dried for?

apologies if this doesnt fit the sub/flair, ill remove if i have to

i was going thru some old books on my shelf and found two dried leaves in one of them! which is pretty exciting just by nature of discovery, i guess.

i was wondering if there's a way to approximate how long a leaf has been drying for? just so i can better know who it was that left them here, since it couldve been basically anyone in my family.

and then, out of curiosity, what happens to leaves that have been left too long? google searches show pressed leaves can last between five and seven years, but what happens when their time is up? decomposition, i guess, but like. what does it look like? what are the signs? what would be left? does it affect the things around them (i.e the book theyre left in)?

these leaves have been sitting in this book for at the very least three or four years? judging by the fact that i believe theyre norway maple leaves that probably cane from russia and last time i was there was in? 2021? im just trying to say they havent seen a world outside the pages of that book since they were placed there. dark and under pressure

anyway yeah, id love to know if anyone can tell me if theres a way to tell how old these are. if not just dry leaf decomposition will do, its interesting to me 🙂

sorry again if this is the wrong sub for this, lmao