That's a good explanation,but even if we suppose that they shared Angier's vanity,they could just take turns when was show time.

Can anybody answer me why they took turns???I can't seem to find a logical explanation. I mean each of them could have their life with the woman they loved and when Fallon was needed one of the Bordens could dress himself up like him.Thing is,they took turns even BEFORE Olivia came to work for them....