Free replacement is conditional. According to the description of Apple official website, the following conditions need to be met: applicable model series: MacBook, MacBook Air, MacBook Pro. A few keyboards may have one or more of the following situations: unexpected repetition of letters or characters; Letters or characters do not appear; The keys feel sticky or the feedback is inconsistent. The validity period is 4 years from the date of the first retail of the equipment. Replacement steps: To make an appointment for Apple's after-sales service, you need to download an "Apple Support" app, which is a product specially developed by Apple for after-sales service. It is very easy to use. After the download is opened, choose your own device, choose the theme "hardware problem", choose "keyboard is not normal", and finally choose to send it for repair by yourself. Just choose a time when you are free.