I'm the kind of nerd who tracks this kind of thing, so here is a list of the number of months between purchasing each phone I've owned, from newest to oldest:

5, 44, 47, 28, 23, 18, 46, 40

The first number is 5 months from my latest phone purchase to the present day. I'm not looking to replace this device any time soon. The previous two phones I owned lasted a decent amount of time, nearly 4 years each. Before that I was buying cheaper second hand phones that didn't last as long. And if you go way back, the final two devices are pre-smartphone era where phones were simpler with less to go wrong and less need to upgrade.