#2 is overkill. Back up once and forget about it, there is no news to backup after transactions.
If you send coins your wallet generates a new key for the remaining coins.
At that point your old backup is useless - it has a key that no longer works.
And yes, people have lost coins because of not knowing this.
> droffel: Hardware wallets use the BIP32[1] spec to implement "Hierarchical Deterministic" (HD) addresses. Using a single seed phrase (stored internally on the device, and also written down external to the device, neither copy should ever be online), you can generate an infinite number of addresses for your wallet. Every time you request a payment, you get a different address to send to, there is no address reuse (unless you or someone else chooses to send funds to an address that has already been spent from).