For reference, there's 8760 hours in a year. So if you ran that pc 24/7, you could ostensibly expect those GP's for @4.5 years of continuous usage. If you only run the pc for @4hrs a day, those fans'll last more like 20 years, unless abused. While that's theory, reality is you'll get at least 5 yrs out of a pc, then move on up anyways, and no one keeps their old stuff (should say very few do) so case changes mean fan changes. Either of the fractals are premium quality fans, go with what's cheaper.