流水不腐，户枢不蠹 (流水不腐，戶樞不蠹) liúshuǐ bù fǔ, hù shū bù dù

liúshuǐ bù fǔ, hù shū bù dù phrase flowing water does not rot, nor a door-hinge rust; constant activity prevents decay
Domain: Proverb 谚语
Notes: (CC-CEDICT '流水不腐，戶樞不蠹')