Storing and organizing the library collection gets more tedious with the influx of donated materials which are most often irrelevant to the mission of the library. It is better to store relevant materials than more of next to useless materials just to give a impression of a rich collection.
The most tell tale evidence of an irrelevant material is the borrowing rate for that item. The less time it is borrowed in the last three decades the best it is designated for other uses, like land filling, or some other environmentally friendly purposes. The ones with high borrowing demand ought to be bought in two or more copies depending on the library's financial standing. Often, getting the quality ones, especially reference materials can really deplete book funds fast.
In this age and era, getting electronic materials can be appealing.