I just ordered an open box 2015 MBA 13 (8gb of ram). Not the geek squad open box. Just the regular open box. Came out to roughly $638. I've never purchased open box items before from Bestbuy. How is the condition? I'm worried about premature wear on the battery as well issues with the screen. Also, how long is the warranty valid for? Do we still have whatever is left of the 1 year? Could we get a Squaretrade warranty for this open box? Sorry for the million questions. Thanks.