How often you should change your grips honestly depends on how often you play. If you play or practice more than three times a week I recommend changing your grips twice a year if you only play once a week or once every month I recommend changing your grips every two years because over time they’ll get hard but grips are important so take care of them. You’d be surprised how a warm bucket with Dawn detergent and a scrub brush will rejuvenate slick grips.