I'd like to quickly plug Fairphone here. They've made a phone which does everything you'd expect of a smartphone, but is also very easy to disassemble. Replacing the battery is extremely easy, same with the screen itself. The other "modules" tend to have a few different components on them, e.g. USB plug and vibration motor are on the same module AFAIR.
I've been using the Fairphone 2 for a bit over 5 years and while it's not an outstanding phone, it's lasted well enough. The challenge for me in Australia is getting spare parts, as they only ship to Europe sadly.
