Some longer CDs such as the ones Wendi makes have several tracks on them, each track being 20 min 0r so. It would be like having 2 or 3 paraliminals on one CD. I wouldn't listen to a 70 min hypnosis tape unless it was VERY good. I do have a few 30 min and even 45 min hypnosis tapes but I haven't listened to them in years. Having the tapes as short as they are is a good thing IMO. It is easier to put aside the time without interruptions on a shorter tape.