Weeding of the library collection should be a regular, continuing, and steady process to ensure the full use of space in the book collection and the development of a vital, useful collection.
Regular weeding should occur in the following cases:
- A new title supersedes the older title
- Duplicate copies of titles that are lightly used are available
- Books have become obsolete in context, style, or theme
In the areas of pure science, all ordinary textbooks or books of general works can usually be withdrawn after ten years. Applied science books are usually dated after five years and definitely after ten years in such fields as medicine, inventions, radio and television, gardening, business, computers, etc. In history, materials that are deemed inaccurate or unfair interpretations, works of travel over ten years old, and contemporary writing now recorded in basic histories.
In biography, the library strives to keep collected biography, but individual lives of persons whose importance is no longer great may be withdrawn after ten years.
Any book in the non-fiction field that does not carry an index or a bibliography should be carefully considered for weeding after ten years of use.
In fiction, works that have not been used more than three times in a five-year period may be withdrawn unless the work is considered a classic.