I learned from @Stuart_Ward at Fixfest that a few of the older Thinkpad range of laptops have drainage system to try to safely drain out liquids when spilled on the keyboard.
I always knew the older Thinkpads were recommended for their quality of design, but I had no idea about this particular feature. Love it. As far as I can see newer Thinkpads are made spillproof by sealing the keyboard up rather than letting the water drain through. Which works too but I would guess also makes the part harder to disassemble/replace.
What are some other examples of hardware designs that promote longevity?