The Library Depreciation ReserveFund (LDRF) is a type of reservefund especially for public libraries under Montana statute:
22-1-305. Library depreciation reservefund authorized. The governing body of any city or county or a combination of city and county in Montana may establish a library depreciation reservefund for the replacement and acquisition of property, capital improvements, and equipment necessary to maintain and improve city, county, or city-county library services.
22-1-306. Moneys for library depreciation reservefund. Moneys for the library depreciation reservefund are those funds which have been allocated to the library in any year but which have not been expended by the end of the year. Such moneys include but are not limited to city or county or city-county appropriations, federal revenue sharing funds, and public and private grants.
22-1-307. Investment of fund. The moneys held in the library depreciation reservefund may be invested as provided by law. All interest earned on the fund must be credited to the library depreciation reservefund.
The library may want to establish a library depreciation reservefund to pay for major repairs and upgrades.