Old titles that are well loved and used by students have to be in bad condition from all that use. Weed and replace them. If they are old and yet still in good condition, then they are probably lacking in visual appeal and should be weeded also. An old book surviving in good condition in a high interest area should tell you something. The AV collection is another story.
Old titles survive here due to the more limited and protected circulation.
In fact, if you have videotapes that were converted from old 16mm movies, you may have a collection that is even older than indicated by the date on the cataloging. Look for presentation here - both dated visual images and playback quality. All about snakes, 1956. Amphibians and reptiles, 1969. Amphibians and reptiles of western North America, 1954.