What sort of an institution is this? Does the IT department there serve the cutomers or is it the other way around?
a) What if a student wants to refer to a subject he learnt last year?
b) What if a teacher needs to remind, revive a topic from last year (or the one before)?
c) There is something called "course development", and this development continues over the years. Your staff meekily start from scratch every year?
d) Any serious institution is accountable for their work a certain number of years. Your IT purges them?
Sure you can't keep archives endlessly. People plan these things first and then give the IT their part of the job. (I think, this is what Tim and Emma were talking about.) What your institution has is an administrative problem. I do understand if you do not want to pass this information to your authorities.