For the best shaving result, it's important you replace your shaver head after 1 or 2 years. When you replace the shaver head, you maintain the quality of the electric shaver. What's more, clean blades prevent skin irritation and acne. Do you have a Braun electric shaver? Replace the entire shaving cassette. On a Philips electric shaver, you only replace the razor blades. Which shaver head you need depends on which electric shaver you use.