way too early.
I want a required "Good till" date printed on them, that guarantees they last at least X days, just like soda.
Yeah, most of them will last a lot longer than the printed date, because chances are you won't buy them and install them on the day they make them.
But still, if a curly bulb is supposed to last 5 years, and it dies one year after you install it, there should be an easy way to get a refund.
And just how do you propose to prove the CFL only lasted less than the rated life? It doesn't have a built in run timer, the serial number on the bulb is typically too small to capture with the average cell phone camera, and you can't expect the stores to track when they sold each and every bulb (Google probably would).
Even if you could prove that it failed early, then you get into the arena of the manufacturers adding usage direction that say "This build may only be run X hours per day. Any usage out side of this, voids your warranty"