Redundancy is a key idea in all games, and more importantly in game development. In the games it's important to have familiar objects, you can't constantly introduce new material to the player for a myriad of reasons simply put only a few select people will continue to play such a game. So whether it's health pickups or weapons you need something the player can recognize and understand quickly to have a framework for the game.
In development redundancy takes on a new form, starting with backups and copies of everything you do, and not just one file here or there but many copies of each version of each thing you do. Sometimes it's necessary to backtrack or gain inspiration from an older iteration which might end up being used in a different game. Then there's always hardware failure to consider, something which I've been struggling with the last few days though thankfully I had the forethought to have copies floating around so I didn't lose any valuable data.
You'd be surprised at how much gets reused in games some times. Sadly you might though in same cases in which a game overuses the same things too much. Case in point might be dragon age 2 in which there were only a handful of areas you could travel to, all different versions of the exact same map. Yet you wouldn't notice the constant re-using of trees for example or think about the many instances of the same weapon in other games. It's unlikely you memorized the face of every zombie in dead rising or left 4 dead and I can assure you they're not all unique snowflakes they're just copies of the same file being re-used in a way you don't tend to think about to enhance the game.
Often the answer in a game on how to do something is a carbon copy of something introduced earlier in the game or a combination of things introduced earlier, sometimes introducing something new in the process. For example in portal you learn cube+button=exit then you learn how to get the cube to the button using a hole over a doorway a small subliminal message that leads you to putting the cube through the portals once you get them. From there on the puzzles become more complex introducing new ideas on how to get the cube to the button, such as momentum and portal placement. These elements of game design also fall under the category of redundancy. Using the same bag of tricks in new ways to engage the players in what is perceived as meaningful play. This principal also applies to movies as well, next time you have the chance think about how much of something you're playing or watching is being reused from earlier in the game or movie or clearly copied over from a similar game or movie.