This is where buying "professional grade" does often save you. I have seen tons of Dell Latitudes and Lenovo Thinkpads that look like a black brick but are still going 5+ years later. They actually invested in thermals and it shows. (Written on a 7 year old Thinkpad).
I had to repaste the CPU in my old Thinkpad after a couple of years, but overall I got several years of hard use out of it (including playing games on it in hot apartments) before I destroyed it with an unplanned rapid deceleration.
It's funny you should say that... I just bought a 6? year old Latitude E7470 for £189 last week.
I had one years ago and it was built like a tank. Also, the screen (2560x1440) is possibly the best I've had on a laptop and the keyboard has particularly deep and solid travel making it the best typing experience I've had on a laptop too.
So, best laptop I've had tbh.
It's only an i7 6600U so not mega powerful but I don't write 2M LOC apps anyway so it's fine.
Just waiting on 32GB RAM arriving (official support is 16GB but the chipset supports 32).
I agree 100%... business-class laptops (and printers for that matter) all the way.