Don't do it if you are buying it from an unknown person on the internet that you don't know and have never met. It might look like a good deal, and probably is if you are getting if for like 50% cheaper than a new one, but it's not really worth the worry. If you are buying a hardware wallet, it's fair to assume that you have or will have an amount that you feel is big enough to store on such a device. If that is the case, don't make shortcuts and try to save a few bucks by increasing the chances of hurting your crypto holdings.
Imagine if you have a really expensive car. Fill the tank at a gas station and don't trust the guy at the corner who says he can get you the same quality fuel for half the price. If you can afford the car, use quality fuel with it and not something that could be mixed with water or other fluids.
![Wink](https://bitcointalk.org/Smileys/default/wink.gif)
After that, send a small test amount to your wallet. If hardware wallet is unreliable, then this money will be stolen immediately.
Not necessarily. If there is some automatic drainer, then yes, the sum would be stolen and sent to an address that the scammer controls. If that is possible, of course. Let's not forget that hardware wallets require physical confirmation to send transactions.
But if there is no drainer and someone is manually checking the addresses, they could wait. Let's think like scammers. If I had control of your keys and I am planning to steal from you, I am not going to do that after you send $5 worth of crypto to your wallet. I will wait a little, maybe for $500, $5000... Only then will I react. Doing it earlier will show you that something is wrong, and you would probably abandon the wallet. So, I'll wait.