Apple's portable Mac notebooks like the MacBook, MacBook Air, and MacBook Pro are all powered by Lithium-Ion batteries, and these batteries don't last forever. They go through cycles as they're charged up and used over and over. After a number of cycles, batteries tend to lose their effectiveness at storing power, and will eventually need to be replaced.
If you have ever wondered just how close you are to needing a battery replacement in your Mac, then you'll be happy to know that macOS is actively monitoring your Mac's battery and can tell you with a quick keyboard shortcut, which we'll be discussing in this short information piece.