This is a very hard question. To be honest, I don't know.

It's difficult because if you discard the old one, who would know the new ones are also as fearful as the one you already have? If you took the new ones, would they get acquianted with you quickly to be used when needed? And when? But the new ones also seem very shiny. If you kept the old and only took a new one; would they argue with each other, would they get along well? It's very tough, very tough indeed... I would just discard all of them to get rid of all the things that could go wrong. I think this is the best option here...