What is the approximate lifespan of the OnePlus 3?

I’m planning on getting the OnePlus 3 as my first smartphone ever. I’d like to know, though, its approximate lifespan before it starts to act up and lag just like my mom’s iPhone 4. Any OnePlus 3 or OnePlus users out there care to give me your opinions? There’s a OnePlus service centre near me, so I needn’t worry if the phone acts up, I just want to know how long it’ll take to do so. Thanks! https://linustechtips.com/main/uploads/emoticons/smile.png