If a work is personally meaningful, even if it carries no monetary value, you should consider preserving it. The medium, or materials used to make an artwork, will determine the necessary care of the piece.
In general, when displaying or storing artwork, keep the material away from areas where it will be exposed to direct light, high temperatures and humidity. Paper items should not come in contact with materials that contain acids or impurities that could damage the item. When packing or storing artwork, use archival supplies meant for conserving documents, photographs and art.
An excellent book source is Caring for Your Art by Jill Snyder. The American Institue for Conservation (AIC) has a section, Caring for Your Treasures, that has downloadable guides. The Library of Congress also provides useful advice on preserving works on paper (drawings, prints, posters) and on caring for books, photographs and videos.