Is Pimsleur effective at learning japanese in a fast pace?

According to the "official" instructions you're supposed the learn 1 lesson per day (there are 90 lessons total, each 1/2 an hour). But seeing as I have no life, why not learn 10 lessons per day? After I finish them all I thought that maybe instead of practicing by listening to lessons again (which is boring), to just play them while I do other things and not really paying attention. Is is effective to some degree?