i am really confused about the gadget wallet. if it broke, touched by water or technically unfunctionalized there would not be any way to save the coins in the gadget wallet. but on the other hand online wallets also might have many safety quastions. gadget wallets or online wallet? has quastion marks for me:/
If you're referring to hardware wallet then while you are creating and installing the firmware for the first time, the wallet will give you a list of words that you should keep safe. If the hardware gets broken for some reason, you can recover your wallet using the list of words that was first given to you.
Having several backups increases the risk your seed gets compromised. It's a trade-off between the risk of losing the seed, and the risk of someone getting his hands on it.