I recently acquired a MacBook Air. It's a 2011 model, got a dinged corner, but works just fine.
My boss discovered that I had this device, and he mentioned that his son had one exactly the same and it wasn't dinged. Would I be interested? Sure, I'm always interested in gear, so bring it in and let me have a look.
He brought it in and I got a chance to check it out. It turned on straight away, but wouldn't boot, just brough up the folder with a blinking question mark in it. Questions were asked, and he had erased the hard disk in preparation for a sale. Makes it difficult to evaluate.
I looked up the Apple keypress codes at startup, and started up an Internet restore. Several hours later, I had an operating system on it and could check out what it was. It's exactly the same as the one I already have. 2011 model, 4 gig RAM, 129 GIG SSD, 11 inch MacBook Air. Battery is about two-thirds through its life. Everything works, even the down arrow. Nice.
There is one big difference between these two machines. The first one with a ding has been used for 5 years by a student with long fingernails. The keytops are a little scarred, and the down arrow works poorly, but the keyboard is lively and bouncy. This new one has been used by an active programmer for 5 years. The keyboard has been pounded. It's not bouncy, it's tired. But it all works.
What to do? I don't like letting deals go, so I got this one too. One for home and one for work.
I configured it the same as the other one, got them both working exactly the same. XCode and MacPorts. Looking good.
One problem was the name they show on networks. They both defaulted to "Henry's MacBook Air". I decided to rename them appropriately. They are both MacBook Airs, but one has a bent corner and one does not. They are now known as "AirBender" and "AirNoBender". Easy to tell them apart now.