Just because it is in a sealed box doesn't mean it is new and unused so make sure you check the run hours.
EXAMPLE: Bought a new laptop several years ago. Took it home in a sealed box.
Was not new. Found the previous owner's email messages, etc. on the laptop. Emailed him and found out he returned the computer and the store may have sent it back to the manufacturer (doubtful) but all that was done was that it was put in sealed packaging and returned to the shelf with the previous owners personal info still on the laptop.