In 18 months, your Braun shaver cuts an average of 6,000,000 hairs This causes the cutting parts to gradually wear down, which can result in a less comfortable shave. Therefore, Braun recommends that you replace the cutting blade and the scissor head every 18 months to keep the shaver in good condition. Take care of your shaver, and it will take care of you. TOP PERFORMANCE: Braun recommends replacing the shaving head every 18 months for continued excellent results EFFICIENT SHAVING: four synchronized cutting elements that do on the first try what others do on two (proven on 3 days of beard growth. IPI Research Institute, February 2015) SMOoth SHAVING: strong> with this shaver head's 360-degree adjustment, for easy shaving even in hard-to-reach areas EASY CHANGE: it's easy to change to a new shaver head - just click QUALITY CRAFTSMANSHIP: 100% made in Germany and compatible with all Series 7 shavers (new generation)