Balancing beads will typically last for the life of the tire. Although Counteract Balancing Beads are durable and will not break down, the moisture resistant coating does wear down over prolonged periods of time. We have observed cases where our beads have lasted 400,000 miles on a commercial drive tire with little to no wear on the beads themselves, so this is typically something users do not need to worry about.
Some materials used to balance tires do breakdown sooner than others such as ceramic, which becomes brittle over time with the heat fluctuation, or larger beads that have a larger force of impact when slowing or stopping. Once the materials break down, they become abrasive and can eat away at your inner liner. This is why we use 1mm diameter tempered glass beads, which are designed to not only last longer, but to also avoid any damage to the inner liner of the tire keeping it cooler and increasing tire life.