On 2014-09-03 Adam Thompson wrote:
The obvious analogy that for obvious reasons* won't have occurred to you: cars. If you don't get a lemon, it's probably good for a while, but eventually starts to break down. Also, historically, humans - at least in ages and places where infant mortality is/was a significant drag on population growth.
The Cars example is imperfect, because, as you said "it's good for a while", but with hard drives I find that the near-zero-failure part of the bathtub, if it even exists for HDDs, is abominably short, like 6 months. Most quality cars these days (ones ranked high in Consumer Reports reliability) should be nearly trouble-free for 5 years.
Here's my interpretation of the HD curve (monospace required):
| | ____________________________ \ __________/ \ _________/ \ / __/
The main point being that after (maybe) a short reprieve, the failure probability immediately ramps up to and sits at an unacceptable number (like 15%) nearly forever, with but a tiny increment after each additional year. Whether there is a bathtub end after 10-20 years, is up for debate. (Brad and I have Atari ST drives from 30 years ago that still operate, for example.)
Surely if you ASCII'd a modern car graph it wouldn't quite fit?
Your human being analogy is probably much closer to what I'm looking for, but that one definitely has an abrupt bathtub hockey-stick at the right hand side :-) With humans, make it past the first tricky year and you probably have a small chance that stays relatively static for dozens of years of contracting a terminal illness or getting hit by a bus. Not as straight-forward as a "light bulb" example as I was looking for (as it requires some thought and reflection) but pretty good.
Surely, though, in the world of consumer items something else must be just like hard drives?