Imported GPS units, total stations, and electronic levels have a normal service life of 8 to 10 years. Imported theodolites have a normal service life of 5 to 7 years. Domestic theodolites and imported levels have a normal service life of 3 to 5 years. Domestic levels have a normal service life of 3 years. Equipment exceeding its normal service life and no longer functioning properly may be submitted for scrapping. Instruments experiencing malfunctions before reaching their service life should be repaired. For malfunctions not caused by human factors, if repair fails to restore the instrument to its required accuracy, it may also be submitted for scrapping. The unit using the surveying instrument shall return the instrument to be scrapped to the surveying team. The surveying team shall submit an application, which must be reviewed and approved by the Chief Engineer before scrapping can proceed.