I prefer external drives mounted in metal (usually Al) boxes for the better cooling. But I've not actually measured or tested whether or not the cooler metal box enables longer drive life.
Question for anyone who knows: Is it worth it for the home user to buy 'enterprise grade' drives?
As you might suspect, the answer is
it depends.
There are variables, such as what are you using them for, are they stand alone, or in a RAID configuration, and of course the enclosure are they mounted in also plays a role. I like and use an Icy Dock 2 bay enclosure, which runs very cool, 88˚ by IR thermometer. It can handle RAID or JBOD setups, and I use one drive for Time Machine and the other for periodic Chronosync bootable cloning. Thsi allows me to hot swap drives at will, no trays required, and it can use HDD's or SSD's. It will take drives up 8TB per bay, and it's tool-less. An excellent enclosure, IMO.
http://tinyurl.com/y9epb2rbtom's HARDWARE has an interesting article on consumer vs enterprise drives.
http://www.tomshardware.com/forum/252706-32-consumer-enterprise-grade-harddrivesHeat is an enemy, but so are temperature swings, hot-cold-hot-cold ad infinitum, with HDD's. When using spinners it's time to consider replacement when the warranty period ends. Some spinners last much longer, but, what if they don't, and they contain info that you don't want to lose or compromise? I think the jury is currently still out on SSD's, WRT lifespan.