Make sure you use the wallets from the Ledger website. If the device works with them, then you shouldn’t have any problems in the future unless it gets physically damaged or lost. And in that case, the recovery words you write down (don’t save them on anything other than paper) can recover your wallet on any other Nano S device. If it’s a fake device, the Ledger chrome app wallet will tell you it isn’t genuine and won’t work.