Would it help the health of the cards if the intensity is put on 12 or less? The Hashfaster pools advise an intensity of 11 for Scrypt (which will not give max perf. but will increase desktop usability and might help avoiding unnecessary wear).
Many people are not willing to sacrifice hash rate. But you can often decrease voltage and clock speed with very minimal impact on hash rate. In fact one of my R9 280X works best undervolted and clocked to 950 MHz getting +700Khash. And the difference in temperatures and power consumption is quite big compared to default stock settings.
Even +-20 MHz difference in GPU or Memory frequency can mean +-100Khash/s difference and the settings are unique for each card.
You'd have to see how big difference it makes on VRM and GPU temps and a kill-a-watt meter would be very handy to have when you optimize mining rig. After all, electricity is not free either. Mining is a compromise of everything.
The point of desktop usage is valid. At intensity 13 things seem to be a bit slowish. Perhaps it will reduce the load a bit too -> lower VRM temps for example so it helps with wear and tear.
(Do note that I 13 is optimal for Tahiti and I 20 for Hawaii)
Main reason cards die is that the default gaming settings are just too much for 24/7 "furmark-like" use. And people only see the hash rate ignoring card's hints of suffering.
One serious stress to GPU comes when you sometimes lose connection to your pool stratum server and your GPUs rapidly cool down to idle temps and when work resumes it rapidly heats the GPUs back to very hot. This kind of cycling is very bad.
"It's designed to run at 94c. VRM is spec'ed up to 130c" - anonymous miner
"My 5 HD 7990s are running each at 99c" - anonymous miner
In the mining pool chats and forums you find quite a bit dead hardware.