Sorry for the (maybe) stupid question, but I'm waiting for a replacement of my Kindle Fire HD, since it's under warrantry.
I saw Amazon sent me a refurbished one, and I never bought any refurbished device. My question is simple: is the device reliable? My old Kindle had a charging problem (the battery would last half the time it should), so I really don't want to risk to receive a defective product. I can always send it back since it's covered by warrantry, but what's your experience with refurbished Fire HD?

Refurbished anything is fine when it's solid state like that. If it works right out of the box for you, it will continue to, most likely. I don't recommend refurbished anything at the really high end, but a Fire is a really, really simple device. It's a screen, plus a little bit of storage and little more than an abacus to do math. It was probably returned by someone who didn't like it, or traded it in for a newer version. Refurbished mostly just means it was cleaned and then tested to make sure it still works - and, again, since it's all solid-state, there's not much to break.

Next week it will arrive, I hope the battery last 7 hours like it should.