One of the few things you can count on is that Apple will release a new iPhone every year, a new and improved model to the one you just bought. By the time the new arrives, they are already classifying the old as obsolete and dysfunctional. So, contrary to popular belief, they don’t put that iOS 10 update on your iPhone 5s to make it better. “Planned obsolescence” is the term many people use to describe Apple’s decision to push problematic updates to all previous models to cause issues with batteries, apps not opening, connectivity, and other issues. These updates will slow down your phone, and with enough updates on an older model, it will make it obsolete.
There’s no reason you can’t get four or five years out of your iPhone before upgrading to another. They are well built, quality phones made to last. However, these upgrades can reduce the lifespan by as much as two to three years. Therefore, anyone with a functional phone below the iPhone 7 should ignore these prompts; Ideally, you should still be on iOS 8 or 9 for the iPhone 5 and 6 series. The software that came with your phone already works perfectly fine.
Also remember that once you update, you will not be able to revert it. Apple will try to force you to update in many ways. One such tactic is that sometimes your phone will ask you for the passcode, but it will write in fine print that doing so will automatically update the phone sometime early in the morning. An even smaller button below to opt out of this automatic update is the only way around it. Another means, even harder to avoid, is that developers will update popular apps like Facebook and Snapchat to be compatible with the newest iOS, creating a disparity between their operating system and the app’s. To continue using it, you will most likely need to update your system. Wait as long as you can and then stop using the app or upgrade, but stay informed about your choice.
The bottom line is that if you upgrade an older model, you can essentially turn it into a paperweight. The battery and charging port can be fixed, just like other things, but repair shops can only do so much with an upgraded phone because a lot of the time, the phone will just cut off new batteries or chargers. Be aware of what you’re doing with your phone, and also consider the impact of buying a new phone each year.