So.... maps, (the pre-designed ones by Paizo and WotC).
Dungeon maps have a reuse-ability problem... sort of. If it's a map that you have used before, the players will know where the doors are, the layout, and if it is printed on the map then they will know the secret passages. There is also the problem that (even if it is a new map) you have to cover up undiscovered areas with paper or your players will see all of the routes and doorways.
Well I have an idea about that.
What if you had maps that showed blank rooms but NO DOORS. Like this...
Will the players know which path to take? Not without doorways linking rooms. Now how about you place door standees as the players discover them? And you place (or draw) room decor as the enter? Instant Fog of War without having to deal with a mess of tiles or cover sheets. And because you can place doors in different locations each time you play, you effectively change the map, keeping your players guessing. And you don't have to use all of the rooms either.
I would say that 3 different maps would give you hundreds of dungeon crawl combinations.
You don't have to wait for me to make maps for you. If you are hand drawing maps based on your favorite rpg's designs, try leaving out the doors until the players find them.