I have yet to have a PDA die on me period...they have all been fully-functional until I crated them up in favor of a newer model. (My Dell Axim X30 High has been used daily for the past two and a half years and is still in my pocket.) Thus, I don't see the need to purchase an extended warranty, though the experiences of others may differ.
Another thing to note is that Dell is exiting the PDA business, so an extended warranty wouldn't do much good. (They will continue to sell accessories and provide basic support, but it may be limited.)
Im thinking about getting a Dell Axim X51v; should I get the extended warranties? Dell offers two warranties: the "Limited Warranty" and the "CompleteCare Accidental Damage Service" are these worth the extra money? Or do the one year warranties suffice?