Braun replacement foil & cutter blocks help to maintain your shaver’s maximum performance. Braun recommends changing your shaver’s blades every 18 months as the cutting parts will gradually wear out over time, and your shave may become less close and comfortable. After replacing them you get back 100% of your shaver’s performance. Braun electric shavers are designed and tested to last at least 6 years with proper maintenance excluding shaving cassette–use as indicated. Within 18 months, your Braun shaver will cut an average of 6,000,000 hairs–equivalent to shaving an entire soccer field. In accomplishing this substantial task, the cutting parts will gradually wear out and your shave may become less close and comfortable. Therefore, Braun recommends changing your shaver’s foil & cutter block every 18 months to maintain your shaver’s maximum performance. For a perfect shave every day.