I'd rather get the best hashrate out of my gpu to get closer to my ROI than been worry about life span, your card can't last a lifetime for mining because difficultly grows bigger every year meaning at one point it will become obsolete, avoid high overclocking and use the most stable settings possible, that's all you'd ever need
There is an issue with this line of thought, do you maximize the residual value of a GPU? or cook the card? Probably the two best answers to this question are the 480 GB nitro+ sapphire card and the EVGA 1080 ti. Both have held up in value, still do a decent amount of hashing and were not too bad cost wise. The 1080ti is particularly noteworthy because it has/had good mining flexibility.
One other point to note is that the higher efficiency (W/Mhs) is at the lower MSI AB settings. There is a message there.