hmmm. 1 year thats it? how come?They're JLs? 567 years. Unless they're the glorious dub sevens. Then it's at least double that.
In all seriousness, probably a year, I don't know. It depends on how well built that particular woofer is built, if there is anything unusual that's wrong with it that happened during construction and wasn't caught by quality control. It depends on how much power you give it, how much you clip it, etc.
It's hard to give you a quantitative value.
you forgot:then they'll end up as doorstops, cereal bowls, hats or in the garbage.