Still rocking an iPhone 8+ here from 2yrs ago. When one hasn't had the chance to use anything else but, the iPhone 8+ suffices because I probably don't know any better. But the thing is, there's always better, every single year. How much money are you willing to front every year for a different experience? Considering the cost of smartphones these days, I am comfortable with sticking it out for 2-3yrs. The only reason I got a Pixel 3 XL recently is because under contract it only costed me a measly $100 over the course of 2yrs, so to me that's justifiable. My wife is still on her Samsung S7 Edge from 3-4yrs ago that's becoming less and less tolerable, and will probably move to an S10e or XS Max in the next few months. I think to reduce cost, and seeing how powerful phones are, even last year's flagship phones at a more reasonable $500 is a great option.
The 8 series should have another couple years of support, so if you can find one at a value price sure why not.
everytime.