There are a lot of refurbished, used and sometimes duplicate products of an original out there. A good deal might not always be a sound one. How can you be absolutely sure that you're giving up your hard earned cash on what you really intended ?
Well in the case of Apple products it's quite simple.
Just visit: http://checkcoverage.apple.com
(kindly note Apple takes this down for maintenance sometimes, but it's always back in a few minutes)
Here's what the page looks like:
Once here, enter your hardware serial number (you can also enter the IMEI) usually found on the back of your apple product.
Now, there are products in several stages of life;
1. Non-Active Products:
A non-active product is in mint condition. It's never been taken out of the sealed or wrapped packing and is completely new and unused. These will have 1 year Apple International Warranty from the day you activate the product, meaning a 1 year international warranty coverage from the day you actually start using the product. There is no worries in purchasing a non-active product as it's covered under the 1 year international warranty and is in mint condition.
Here's the image of a non-active Apple product from the link provided;
It's asking to activate the product as it's non-active (serial number removed on the image for security):
2. Active Products:
Active products are those that have been opened and used, may it be even for a minute, and the 1 year warranty period has started it's count down. Active products can be in perfect condition, but it's definitely been taken out of the box and opened. When purchasing an active product, check the inside of the box (even if it has been sealed with shrink wrap - which is not a hard thing to do - making it look absolutely in mint condition) and examine the product. If it's to your liking, visit the site mentioned above "http://checkcoverage.apple.com" and enter the serial number or the IMEI number to check how much of the warranty period is left. If it's good enough for you, go ahead and make the purchase as any issues will be covered under warranty in the period that's left.
Here's the image of an active Apple product from the link provided;
It's showing that the phone is activated and how much of the warranty and coverage is left (serial number removed on the image for security):
Duplicate products will not show up on this link and any refurbished items can be identified from this link as well.
Do not attempt to repair your Apple product with a non authorized outlet as this will void the warranty.
In all cases, Apple will replace (to a completely new non-active product) or repair your Apple product without any charges if it's under warranty. If the product is out of warranty and you do need repairs, Authorized apple service providers will cost a lot but will ensure a fool proof repair along with a limited warranty period for the fix. If you know a company or service provider that's renowned for good repairs or fixes, and doesn't cost as much, feel free to go along with them if the product is out of it's warranty period.