I would never buy a used hardware wallet because I agree with @Meuserna that there's really no point in saving a few $ and wondering if someone modified the device so that even a reset doesn't guarantee that the private keys are safe. Of course I understand that some people simply can't afford new hardware wallets, but if you're going to buy a used device, make sure it's from someone you know, not a complete stranger online.
Thankfully, DIY hardware wallets (
Krux) exist in this case, they're more affordable, especially for those who can't afford a Trezor. Air-gapped wallets are even better and more secure.
DIY wallets should be more encouraged.
In fact, buying a used hardware wallet will always be insecure, and any user with even the slightest understanding of digital security will never deposit large amounts into it.