Apple is oft criticized for selling expensive devices. I find that their devices have much longer life — both in build quality (les prone to falling apart) and software life. This is an hand me down iPhone 5s from 2013 that I have been using as my secondary phone. I just updated it to run iOS 12. No trace of lag, works great.
I think the longevity works in Apple’s favour. Many of these older devices find their way to people who may not buy a new phone in a hurry. This helps in cultivating future customers.
Another hack, when you travel, drop in a local phone shop and check the resale value for popular phones. In particular, I will recommend the phone shops in Phnom Penh – they are open till early morning and are a surreal slight.