I suspect it does vary quite a lot based on usage. We live in a fairly cold place (Wales) and my girlfriend's phones tend to suffer more than mine do, as she sp

I suspect it does vary quite a lot based on usage. We live in a fairly cold place (Wales) and my girlfriend's phones tend to suffer more than mine do, as she spends a few hours in an exposed place most days. Towards the end of its life her iPhone SE was suffering from some truly impressive battery woes when she ventured outside. My current phone (an S8 Edge) is doing relatively fine by comparison, but my last Nexus device really struggled here too and I ended up with poor battery life within a few months. The problem I have with the software approach to battery optimisation is that it doesn't accomodate for environmental issues like that, whereas a bigger battery does.