Some people replace them as soon as new models come out, others don’t.
I need a smartphone for business purposes. I avoided getting one as long as possible.
This month will be six years since the iPhone 5S came out. It cost me $100 from Verizon and a year’s extension of my contract.
On 09/20 I will have been using it SIX years. I see no reason to replace it. I don’t need more storage capacity. I have no music on it. I take pictures for business purposes and as soon as I send them to my computer and know they are saved there, I delete them from the phone.
I have never broken a phone so I can’t speak to repair vs. replacement.
My kids laugh at me for using an older model. There is a drawer in the office with their discarded iPhones: 6s, 6Splus, 7, 8 10, etc, etc. Maybe the grandchildren will use them someday. Mrs. CTL still uses a flip phone. She keeps it in the car for emergency use only, never brings it into the house.