Like to by a used MBA to replace my windows 7 ASUS Zenbook. What should I look for. My main uses are email and web surfing. Also travel extensively. I usually watch movies on my IPad Air 2. Would like a 256 SSD or better and 8 mb ram. So I guess one of the importent things is the build date. I'm also aware of apple's refurb's. I don't do much photo editing or high demand computing. Also 13 or 11. I like the 13 for its sad card slot for future expansion but like the smaller 11.