All phones slow down over time. As hardware gets older and software gets newer, it’s inevitable. But there’s another reason your iPhone might be slow: the battery. This phenomenon was first proposed in a Reddit thread, and then subsequently in a blog post by John Poole at Geekbench. Now, Apple has confirmed that it slows down iPhones with aging batteries. Here’s why it happens, and what you can do about it. Apple Throttles Performance as Battery Health Decreases As your battery gets older, its health degrades. Over time, the battery is able to hold less and less of a charge—so a battery that lasted 12 hours when it was new might only last 8 after a few years under the same conditions. This is normal, and it happens on every device you own with a lithium-ion battery: phones, laptops, tablets, and even other gadgets like smart watches. There are some things you can do to prolong a battery’s health (like avoiding full discharges, and keeping it away from heat and cold), but it happens to ...