I only ever buy some cheap shit when my last shit bucket phone starts packing in and hasn't received a security update in a while. I try to drag it out as long as I can but the budget phone makers seem to be getting more scummy and supporting their phones for shorter periods of time. For the first time in my life I'm getting tempted to buy an apple product.
As to why people buy new every year; from the adverts it all seems to be about more megapixels and ai image processing as phone makers rarely ever seem to boast about anything else anymore, apart from the occasional gimmick. Dunno why anyone needs an extra billion or so megapixels, especially as phone lenses are kinda shit in general.