Batteries wear out over time. We all know this from real world events like having to get your car jumped off and replacing cell phones that die in a few hours. The same thing happens to your laptop battery.
When you buy a MacBook, you buy quality. Unfortunately, the solid build and aluminium case come with a payoff. They aren’t designed to be opened by the owner. And that means, when the battery reaches the end of its useful life, you’re recommended to return the whole computer to your nearest Apple store. Official MacBook battery replacement is costly.