Curious as to if people upgrade from their flagships less often than they would from a more budget-oriented phone.
Do you find it "lasts" longer?
I usually buy mid to low-end phones and tend to upgrade once every 2-3 years, depending when the device stops getting security/major version updates.
I normally get a flagship - generally I find the phone lasts (as in, is not slower/outdated/not getting software updates) longer. I use my phone very heavily in my role, and typically upgrade every 12-18 months, but my phone then gets passed down in my family and ends up getting used (and is still fast and current enough) for another 2-3 years at least.
As an example - the oldest phone we have in the house is a Galaxy S8 which is likely to be replaced soonish, but it's still fast, stable, can do everything the user wants, and getting regular software updates.
If I was to go for older or lower end models, I doubt they would get as much useful life in my situation.