Any time you are storing data, the acceptable number of items to handle are none, exactly one, or a number limited only by machine resources. Don't design a container to hold, say, up to 5 items.
On the other hand, instantiating/specializing a container to hold up to 5 items can be a perfectly reasonable thing to do, depending on the application. It might be a design requirement that a safety-critical program never has to restart due to heap fragmentation, for instance.
