There is no regulation relating to garbage retention, but 3-5 days is the norm, based on the theory that if someone needed to retrieve something or a teller needs to take one more look at discarded documents, e.g. balancing routine, that trash is available.
The Privacy Reg virtually requires that no customer information be readily available on desks, etc. as the cleaning people or others would have access. Also, documents for shedding need to be delivered to a locked bin each night or be shredded and not left at work stations.