If you really kiasu, make 2 or even 3 copies of those DVDs. Keep 1st set to restore (when your hd dies). Keep 2nd copy in a dry cabinet for emergency when you restored too many times and have scratches or when the 1st set starts to turn to get dvd-rot. Once you replace 2nd copy to become 1st copy, make another set of dvd to become 2nd copy.
Keep the 3rd copy for those super super emergency cases.