The most direct answer to the question for me is I doubt that any material will fail me before I fall them. Like many I have Steel, Aluminum and CF and like them all. But if I had to choose one to go with me till my dirt nap it would be hard to give up the CF bike. All other things being equal when I pick up the bike to carry it up or down stairs I notice what bike I have. Close my eyes and I can tell the CF bike every time. Being lighter it feels easier to get up to speed and "seems" just a bit easier for those hills that gravity seems to be making steeper every year. It doesn't make much difference on longer rides either except if there is any climbing I would rather have the CF bike.
So I can see giving up 10 or 20 years of longevity for the equipment for the ease of use for the CF bike. The cranks, wheels, chain, cassette and maybe a derailleur will have to be replaced long before my frame. So assuming I will still be riding for the next 10 to 20 years I will go with the easiest one to get moving and up a hill. However I don't have to make that choice and I will thank you not to give my wife such ideas.
