You can't keep an eye on your computer every minute of the day, but you don't want to deal with heavy or bulky cases either. You use it to surf the web, post on Facebook and other social networking sites, read and respond to emails and even do projects for work or school assignments. If you're like most people, you probably find yourself using your MacBook every day of the week. MacBook Air 13 inch Cases Provide Protection from Everyday Hazards How to Install Screen Protector - Video.Apple Thunderbolt and/or Cinema Display 27'.