Cycling back-and-forth from ketosis to glucose burning?

I’ve been on KETO for 18 mo. and am loving it, however I have heard a suggestion that it might be a good idea to go off of (cycle out of) the strict KETO diet every so often to shake things up a bit. The idea being that the body can get to used somethings and they loose  there benefits.                                                                                                                                                               I made a 2018 calendar that has me eating KETO for 82 days and eating CARBS and low fat for 9 days cycling through the whole year 82 on and 9 off. Mistake or worth a shot?