Replace when shave feels dull: If the razor tugs or leaves stubble, the head may need replacement. Press to lock: Align the head with the base and push down until a click indicates proper fit. Rinse clean: The head can be rinsed under water to remove trapped hairs after use. When to replace: For daily use, consider replacing every 12 months to maintain performance. Single unit: Package contains 1 shaver head assembly; razor body not included.