Periodic valve exercising prevents seizing by moving seats away from ball contact areas where they could cold weld or adhere over time, redistributing lubricants, identifying binding or torque anomalies before emergency situations require rapid valve operation, and providing early warning of developing problems when corrective action is relatively simple compared to dealing with stuck... https://globalsealstech.com/product-category/oil-gas-seals/api-6d-ball-valve-and-lng-seals/