I guess the only analogy I can lend to this is what my optometrist told me about my 30 day disposable contacts from Ciba. Although they're supposed to gas permeable to the extent that they can be worn non-stop for 30 days, including sleeping, he suggested that I take them out one day out of seven with the admoniton "Well, you can certainly wear your underwear for thirty days non-stop, but would you really WANT to?