OK, so you know how many (most?) computer components' failure rates follow the "bathtub curve":
http://users.ece.cmu.edu/~koopman/des_s99/sw_reliability/Image1.gif
They either die quickly due to egregious manufacturing faults, or live a long time (near 0% failure rate), and then all start dying as they get really old.
The bathtub curve occurs in tons of places, like with a simple light bulb.
As per my experience (probably dealing with over 1000 drives personally), and google's studies, as well as anecdotal information, hard drives are different. The failure rate seems to be bathtub-ish. The initial failure rate is fairly bathtub. But the useful-life period is at a much higher level and seems to grow slightly, meaning instead of dropping to near-zero failures during useful life, they drop to around 15% failure rate each year, mostly independent of age. Then, in the old-age phase they seem to ramp up much slower towards death. It's not a hockey-stick right edge, it's more a constant gentle hill slope. We all have seen many drives that are still running after 8, 10, 20 years. In fact, it seems more of a survival of the fittest system (maybe like turtles?), where once they live to a certain age, many go on to live far beyond the average.
Anyhow, my question is, what else in the non-computer world has a failure graph like hard drives? Something easy for a neophyte to grasp. Normal bathtubs have lightbulbs. What analogy can be used for hard drives? I haven't been able to think of any!
Surely there must be one??