I was selling Klipschorns back in the day,(early 70s), and the printed warranty called for 5 years parts and labor. The unprinted warranty was for life to the original owner. We saw evidence of this on very rare occasions.
I bought my K-horns new in Feb, 1978 and still own them. The cabinets have never been opened up and they sound as wonderful today as they did when I first brought them home.
So I guess it all depends on how good of a speaker you bought in the first place.....