I buy things if I need what they do
I do not buy things so that the vendors can maintain sales levels.
My 'phone is some 5 years old. It does what I want, the battery frequently lasts all week.
My main PC at home is 8 years old. I over specced it when I bought it so it still has plenty of grunt. I run Linux so no probs with continued OS support.
Various laptops: still work, I buy them cheap as I need to do little with them except be available when I am away from home & lend to people; they just need to be able to run a browser, Emacs & occasional word processor.
Summary: if it ain't bust, don't buy a new one.