Several places, specifically wal-mart have reworded their battery warranties, so that the term never changes, and you are effectively buying a time frame, and not a product.
IE, you buy a "3 year" battery and you get a replacement or pro-rated replacement for 3 years.
If it fails at the 3 year and one day mark from the original purchase date, you get nothing, even if it was replaced 2 days prior.
