I always get a screen protector for my new phones. When I got my Focus a few years ago I had it a couple of days and quickly got a visible scratch that you could see when it was on.
I got an InvisibleShield for it that did a really good job of hiding the scratch, but it had that orange peel effect that I didn't like. Regardless of that I've bought the same for two other phones since.
This time I decided to get an ArmorSuit for my 920 and give that a try. I'm happy to say that it fits really well, doesn't have the orange peel, and you can barely tell its there.
I should note that the InvisibleShield is also a great product, I just didn't like the orange peel. You won't go wrong with either one imho.