The average Braun shaver cuts 6 million hairs every 18 months. This means the head will gradually wear out and your shave can become less close and comfortable. That's why Braun recommends changing your shaver's foil & cutter block every 18 months to get your shaver back to its best. Take care of your shaver and it will take care of you. Braun Series 9 94M Efficiency Routinely replacing the shaver head keeps your shave efficient with less strokes needed for greater skin comfort. Replace every 18 months Replacing the shaver head resets your shaver to new and ensures it will remain in peak condition for years to come German Quality Every Braun shaver head is made with German craftsmanship How to replace your shaver head Replacing your shaver head is simple. Just press on the sides to click off your current head. To fit the new shaver head simply click it onto the shaver.