(machine's) service life
この機械の耐用年数は十年だ。
The service life of this machine is ten years.
耐用年数が過ぎた設備を更新した。
Updated equipment that had exceeded its service life.
建物の耐用年数を正確に算出するには専門知識が必要だ。
Specialized knowledge is needed to accurately calculate a building's service life.