what do refurbished sets mean?
Taken from the Apple Refurb page:
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Frequently Asked Questions:
(1) What are Apple Certified Reconditioned Products?
Apple Certified Reconditioned Products are pre-owned Apple products that undergo Apple's stringent refurbishment process prior to being offered for sale. These products have been returned under Apple's Return and Refund Policies. While only some units are returned due to technical issues, all units undergo Apple's stringent quality refurbishment process.
(2) What should I expect when I purchase an Apple Certified Reconditioned Product?
Substantial savings
A fully functional unit with complete documentation
The assurance that the unit meets Apple's premiere quality standards, and that its defective components have been replaced by genuine Apple components
The risk that your unit may present minor cosmetic imperfection, such as scratches, marks, discolouration, etc.
(3) Can I purchase the AppleCare Protection Plan for my Apple Certified Reconditioned Product?
All Apple Certified Reconditioned Products are covered by Apple's One-Year Limited Warranty. For extended coverage, you have the option of purchasing the AppleCare Protection Plan with your Apple Certified Reconditioned Product. The AppleCare Protection Plan extends the complimentary coverage on your Apple Certified Reconditioned Product to up to three years of world-class support.
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1) Refurbished products do not come in their original packaging.
2) Interest-free installment payment is available when you purchase online.
3) You won't get to to personalize the refurbished MB or MBP with DVD burner or bigger hard disk.