I have a T440s and a T470. Right now I am using the T440s, because there was record rainfall in my city, and it is humid as hell, and the T470 crashed soon after starting - I think because of humidity. It was working just fine last night after which I had to open all the windows because I lost power.
My next laptop is going to get couple upgrades from the very start. One I am planning is to put conformal coating on major components and that includes entire motherboard.
The T440s doesn't even care.