I have a Chris King headset that I just moved onto my new bike (well new except for about three parts). It's about 12 years old. I can't imagine how you'd expect a better service life than that. However my Cane Creek and FSA cartridge headsets in my mountain bikes have been absolutely trouble free as well, but the whole bike dies long before the headsets wear out on MTBs. Maybe my steel road bike will outlast the vintage King headset that I just put on it.