Ask HN: What's the main block to your smartphone longevity?

Over the years I realised that we all have different reasons to replace our smarphones. I was curious to hear what could make a change in their longevity. These devices have an environmental impact during their production, it's important to use them as long as possible. Apple deciding to bring iOS 15 on the iPhone 6S is problably one best ecological move they could do (hoping the perfs will be fine).

So, what was the reason to replace your previous smartphone?

Too slow? Battery life? Deprecated software? Wanting shining new specs/features? Costly repairs?