Weird, I've only replaced a battery on one phone, my wife's Samsung S3. Here's my history with phones:

1. ghetto feature phone - switched for better features and different service
2. fancier feature phone - had a qwerty keyboard and everything; hinge broke, and I wanted a smart phone
3. smart phone - went through the wash and shattered the screen
4. power button stopped working, and the screen was cracked
5. my current phone

That accounts for about 15 years of phones, so about 3-4 years per phone (I had the first for a year). I didn't need to replace the battery on any of those phones.

I'm more interested in longer software support. My smartphones all stopped getting software updates after 2-ish years, and that's a pretty big deal to me. But I'll take better repairability any day of the week.