Each year a new iPhone is released. Each year a new version of iOS is released. If you're an experienced forum member on MacRumors, you know that you'll see the same threads every year: My device is laggy after updating to "iOS "X.x". You'll see members in this forum claiming that they're older devices are running "better than the previous OS" or "just as smoothly". Is this really true? Are people's devices running as smoothly as before, or are people "glowing" because they're on a new iOS version that they've been clamoring over. Let's put this to the test. Recently I've been watching iApplebytes on YouTube (I have nothing to do with iApplebytes). Their videos prove that the yearly slowdown I experience on my devices isn't a mirage. On all of the the videos I've watched, a new OS slows down a year or more old iPhone each and every year a new OS is released. Eventually, you're left with a device that has considerable amounts of lag...even if it started out as a responsive device. Let's use an iPhone 4S as our example device since it has a history of iOS releases and has been through the two different UI's (iOS 6 vs 7) For giggles, let's take an iPhone 5s on iOS 8.4.1 vs iOS 9 GM In each instance, the iPhone slows down. What once started as a smooth 4s on iOS 5, becomes a lagfest in later releases. While I know some will say that Apple needs to continue moving forward with new features and its natural for devices to slowdown with new software, this doesn't have to be true. Windows has shown us in recent years that you can add new software to older devices without sacrificing speed. Windows 7 > 8 > 10 all build off one another. Its clear Apple will continue slowdown older devices, as its in their best business to do so. I'm not saying that Apple needs to change their practices, it's obviously working for them. The fact of the matter is, it really doesn't matter what hardware Apple puts in their devices, as they will slow them down in a year's time. Your fancy new 6S with "desktop class" hardware will slow down on iOS 10, because Apple chooses to do so...not because the hardware is incapable of running smoothly. This leaves users with two options: #1 - Stay on the OS designed for your phone until you upgrade to a new device. This ensures speed and stability. #2 - Upgrade your software each year to gain new features, while seeing slight reductions in speed with each OS update. I would also love to see someone on the other end of the spectrum prove that their device has "not" slowed down or is running faster than it did before updating OS versions.