when i was on the road Id’d get through one every 2 years roughly but then i’m something of an extreme user. £800+ sony was my ball park. I once bought a cheaper one (toshiba i think), got it home, un-packed it, pressed one key, saw it bend then promptly took it back.
Latest sony was a bit too big and they have gone a bit plascticky but i bought it because it had a full HD screen which apples did not.
I now have a work supplied MBP but if i was buying again i would buy a business oriented Lenovo machine as they seem well built (we have 40 of them on our hire fleet). most laptops are now designed with the home user in mind and are never meant to leave the house.