The warranty is usually effective from the date of purchase.
Can't say what policy is for Maxtor and Western Digital in terms of date of manufacture vs date of purchase.
Interesting I browsed Western Digital's website, they offer an Extended Warranty Purchase for US customers to extend warranty from 1 yr to 3 yrs for $14.95.
http://support.wdc.com/warranty/selecti ... sttype=END
For $14.95 it may not sound a bad deal considering I usually have bad luck with Western Digital usually within the first year or just past the first year.
Q: When does the warranty period start?
A: The warranty period starts from the date of purchase for retail packaged products. For all other products, the warranty period starts from the date of manufacture. Proof of purchase may be required.
Western Digital has adopted a new warranty policy effective October 1, 2002. Western Digital WD Caviar Special Edition hard drives are covered under warranty for a three-year period. All other Western Digital products will be covered under a standard warranty for a period of one year. Products purchased before October 1, 2002 are covered under the product's original warranty, unless otherwise noted on the retail packaging.