While it is a fool who does not order all the shelving that could possibly fit, some sort of justification for specific amounts is generally demanded by architects and purchasing directors. Managers want to know how much you have, how fast it grows, and sometimes if any weeding can be done. How fast it grows is probably the most critical statistic the librarian must provide. Assuming that the library has been in existence for sufficient time, an examination of perhaps the last five years’ records can, as will be shortly seen, give a workable projection. Librarians for entirely new libraries must guess, projecting from their current budget and experiences of sympathetic colleagues. Whether any weeding can be done is partly under the control of the librarian. Most librarians are likely to be reading this chapter because their best efforts at weeding have not succeeded in delaying the need for a new or expanded library.