text: BIP39 hardware wallets - Bitcoin Stack Exchange
  Can I migrate from a trezor to a ledger nano s just by using my BIP 39 word list?
  It is ok to use a duplicate hardware wallet? I assume it is, but would like to hear your opinion.
  asked Aug 19, 2017 at 12:45
  Both Trezor and Ledger support BIP 39 so yes they should be compatible.
  Having the same keys on both just increases the risk because only one needs to be compromised to steal the coins, but it's not a big risk imo.
  answered Aug 19, 2017 at 23:43
  Generally this is not recommended except in an emergency (for example when your device is broken or stolen). The main benefit of a hardware wallet is that your seed never touches a "hot" computer that could contain bitcoin-stealing malware. If you input the seed mnemonic from one device into another device, you will probably need a keyboard to type it... which is dangerous.
  Now you could use an offline air-gapped machine running Tails for example. But even that would be less safe than simply generating a new seed on the new device and sending all bitcoins there.
  Note: The Trezor now has an Advanced recovery system which is a huge improvement, but still not as good as keeping the seed phrase offline.