I still have notes from like second school & I'm in my 20's at Uni lol
It soo pays off like I have been at Uni for almost 3 full yrs and never delete work pff my jumpdrive, and I screenshot all my grades and email interactions with staff and my profs. I haven't deleted barely any of my Uni coursework and I can always go back to them if I need them but it's important not to hoard or disorganise them because then it just becomes useless.
It's like never throwing your textbooks out, would you ever?