It's inevitable that having the public working their way through any number of puzzles and clues, that there are going to be breakage. Players will tug on something that is not meant to move. Or pull and twist off items through sheer inquisitiveness. Unfortunately, there may even be some players who are "light-fingered", leading to the loss of some items due to theft. Following Murphy's Law, if something can break, then be sure as eggs that it will. We follow some basic rules to keep the cost of replacement and repair of items down to a bare minimum.
Have Extras Handy
First things first. For the smaller props, we keep a stock of replacements handy. This will include things like small printed clues, keys, small locks, loose hinges, and all the generic small stuff that's not tied down. Then we have the props and items that are more difficult to replace. Much of the effort to avoid breakage is to design and make these props pretty much bulletproof. They need to withstand daily punishment from heavy-handed players. Though you might think to save money by buying theater props made of plastic or polystyrene, in the full-on escape room gameplay, they'll be destroyed within a couple of weeks. To that end, it's best to stick with real items. Not only will they last longer but also will give a greater feeling to the sense of full immersion. On the whole, anything that doesn't move as part of the game should be strapped, bolted, or heavily glued down. You want to keep all furniture well secured otherwise its movement might disturb electrical wiring.
Check the Puzzles for Wear and Tear
Once a game is in progress it's important that you can see if any bottlenecks are forming around a particular puzzle. That's because a puzzle that causes a back-up is more likely to be broken, as frustrated players try and use more force instead of more logic. It's best if you swap out these puzzles for something that keeps the game flowing. When it comes to resetting a game ready for the next set of players it's important that the game's master checks for wear and tear and replaces anything before it breaks. Whatever you do, don't accidentally leave a duplicate item, as it will throw the whole game into disarray, with players unsure whether they have the right answer or are playing out of order.
Fix down all the Props you can
Another point with smaller props is that you should design the room so that these are relatively close to their solutions. This'll allow you to tie them down with string or a length of chain. The reason will become immediately apparent when you're trying to reset a room and you can't find an important or essential puzzle or clue. Players will pick up things and put them down in the strangest places, leaving the game's master scrabbling around in a panic trying to find them before the next game starts. Remember that having objects that can move can lead to the perception that they are clues. So e sure to screw down everything that's not part of the game to avoid any confusion.
Breakages During Gameplay
If there's a serious breakage of an essential prop during gameplay, then you'll need to have a back-up plan that allows a member of staff or the games master to enter the room and correct or swap it out for another. They will need to be able to enter the room seamlessly, so it appears that their character is all part and parcel of the game itself. This will require some quick thinking on the part of the game master. And speaking of games masters, they must be watching the game/s at all times. You can't hope to stay on top of any accidental missteps, frustrated players, or breakages if your games master is playing on his phone. The customer deserved absolutely 100% of the game master's attention.
Inform the Players before the Game starts
Before each escape room game, the game master must brief the players that this is a game of logic and that there's no force required. Tell them there's no need to break stuff as all the puzzles and clues are within easy reach and are what they are, with nothing hidden to the degree that you might need to smash something to see what's inside. Following on from this, we suggest that you don't let drunk people play. Intoxicated players are much more likely to break things. There's also the safety considerations of drunk people being unable to follow basic instructions in case of fire.
Repair and Mend what you can
We would suggest that either you or one of your staff has at least some rudimentary skills at repairing stuff. Props will break, locks will wear and things will go missing. Though having a backup of everything is very important, the ability to repair and restore items will save you money in the long run. Though a purchased prop might be perfectly adequate for the general gameplay, more often than not it'll have parts that have no purpose within the game, and these can get broken. We suggest that you strip every prop down to the bare minimum so it's sole purpose is to perform the function you need it for and nothing else. The fewer parts involved in props, the better the chance of them being long-lasting. Stripping down props, re-painting and re-wiring are all tasks that can be performed in-house. On the tech side, if you have props that rely on technology, then ensure that you have a manual back up you can insert into the game.