I just had a conversation with a client about having a lock box on site and whether it was a good idea or not. Their concern was about making sure there was emergency access to their property. They were asking if it was a good idea to put a lockbox on. Our typical suggestion is to install Schlage locks or something similar so that you can put in custom codes for quick emergency access. The second-best option would be to put in a lock box. We advise that if that is the route the client wants to go, make sure the lock boxes are large enough that they can fit multiple keys. The larger they are the easier it is to close those boxes.
Be clever, ask a professional.