When we talk about video games, replayability is an oft touched on topic. We like large games that invite players to experience the stories within it again and again. That's why games like Skyrim, Mass Effect and Grand Theft Auto V have such staying power even years after their initial release. As a tabletop player though, it is very unlikely that you'll be tempted to play through the same module or adventure path more than once. Maybe I'm wrong, and this really isn't a thing, but I have never encountered a player or group, who upon finishing off the BBEG and closing the book on their quest turned around and said, "great job everyone! Let's do it again, but this time we'll all play different characters and be total dicks to everyone."
As a DM, I have run the same module more than once, but it has always been for different groups of players. The closest thing we DM's come to replayability is our player's engagement with the worlds we imagine for them. Over the last few weeks, I've been working on creating a world for my players to inhabit. It's a slow process that involves a lot of reading, writing, drawing, rereading, erasing, rewriting and redrawing. In the end we hope to have created an environment that the players can make themselves at home in and really become a part of. The first session, the reveal of that world is one of the most terrifying moments as a DM. Will the players like it or will they spend the next few hours shitting on the world you've spent weeks creating?