I always try to leave a little room for flexibility, where possible. That said, because we do so much research there isn’t a lot of room for last-minute changes. But a few weeks ago we ran into an issue where a topic we picked didn’t have enough information and we ended up switching it out. Often I’ll have a “back up” episode or extra ideas. I find that I often find things that are perfect episodes, so often I will try to fit them in at a later date otherwise I’d be switching almost daily. We also have mini-series’ within our season so that we have specific topics to adhere to, it helps reduce our want to consistently add topics.