New drives can fail whilst sitting in a drawer. Ask me how I know.
My regimen is:
Save to hard drive directory ("orginals")
Save to same hard drive ("backups")
Save to second hard drive ("backups")
Save to DVDs quarterly
AND (this is the important part)
store off-site
Save to external hard drive yearly AND...store off-site
As long as your data is (are?) properly copied and stored as technology progresses, there's no reason digital photos can't outlast film and prints.
Famous last words in my world: "You backed-up, right?"
