How often should I check the buckle and what is the cleaning process?

Periodically inspect and clean the buckle to remove objects or debris that could prevent latching. To clean the buckle, place it in a cup of warm water and gently agitate while pressing the red button several times without submerging the harness webbing or using soaps, lubricants, or household detergents. Allow it to air dry before reattaching. (Page 46)