You can only drag out the inevitable for so long.
A few years ago, my smartphone at the time caught a bad case of gremlins. Specifically, whenever I turned it off, it would turn itself back on and start performing some kind of strange, back-end process. This would completely drain the phone’s battery, which was a problem when I needed it after work. I tried to keep it going as long as I could, even going so far as to yank the battery out whenever I turned it off, but the writing was on the wall: I needed a new phone. While that’s a bit of an unusual example, the fact of the matter is that phone’s aren’t the most resilient devices. If your phone is displaying one or more of these characteristics, you may just have to bite the bullet and get a fresh one.
The battery is the first and foremost concern. Phone batteries wear out over time, gradually becoming less able to hold a decent charge. Depending on how you’ve cared for it, it can also develop other strange problems. Another one of my old phones somehow got its charging port warped, so I had to plug the cord in in a really specific way to make it work, and that was before the battery started inexplicably inflating.
The screen and speakers of the phone are the next major point. While smartphones can be surprisingly resilient, if you keep dropping it, you’re eventually gonna end up with a big, ugly crack on the front. It might still work, more or less, but when you get that crack, you’re officially on borrowed time. The crack will only get worse, eventually impacting the phone’s functionality. It can also spread to the front-mounted camera and speakers, which will make it far more difficult to take pictures or make calls.
But maybe your phone is functionally fine. That’s good! How’s your data storage? Since it’s harder to browse through your phone’s files than it is to browse on a computer, chances are your phone’s memory has accumulated an impressive collection of worthless crud. It can potentially get to the point where there are so many loose files floating around, you’re not even sure what’s important anymore. Your only options then are either a factory reset or a new phone, preferably with a bigger memory card.