Most users get about two years out of their smartphones before finally upgrading. The most recent data indicates the average user will upgrade his or her daily driver after 22.7 months with the device. How do you know when it’s time for an upgrade?
It doesn’t run the latest version of the OS. Android flagships smartphones are typically supported with software updates for two years following their release. So when you buy the latest smartphone, you can probably expect to receive the next two major Android versions. However, it’s worth noting that most brands prioritize flagships, while budget and mid-range devices don’t receive the same level of support.
Performance has declined. Called ‘performance decay’; it’s something due to the fragmented nature of file management on the phone, which makes a mess of its system files over time by breaking them down and spreading them all over the place and hence slowing down the overall performance of the phone.
Battery life has become poor. In addition display and camera quality, battery life is one of the biggest selling points when shopping for a new smartphone. As smartphones become more powerful, their batteries are put under a growing amount of strain. Moreover, every time the battery in your smartphone runs down, its full capacity will be slightly less when it comes time to charge. So on a phone with a non-removable, and sometimes non-replaceable battery, once it has gone seriously downhill, it might be time to get a new phone.
Physical damage that affects everyday use. If you’ve had your smartphone for a while, it’s probably been dropped. These drops can crack displays and break rear panels. Typically, a broken rear panel doesn’t affect usability with dangers of cutting oneself on shattered glass notwithstanding. A shattered display, however, tends to be a bigger problem. Even if the touch layer is still intact, it affects visibility and threatens to cut your fingers. Source: Androidauthority.com