Even the best diamond stylus wears out over time - conical styli after about 500 hours, elliptical after 300 hours, microlinear styli after 1000 hours, and Shibata styli after around 800 hours. For this reason, Audio-Technica has designed its VM95 series of dual moving magnet cartridges so that the styli can be interchanged, allowing the cartridge itself to be used almost indefinitely. So when the stylus is worn out, you don't need to buy a new cartridge; you only need to purchase the appropriate replacement stylus or upgrade your system with a different, higher-quality stylus.