LmL, if you miss just a couple days, when you come back you go back a couple days before you left off and start listening again. If its for more then a week it start to get tricky and you may have to go back a week before you left off. So depends on how long your gone for. The best approach is to keep doing them for the hundred days per schedule as they are put together specifically for this, but you can miss a couple days and go back if you need to. Hope that helps.