Apple's policy:
if you bought DIRECT from Apple, not from a Reseller of any description, you can return or exchange your purchase for a full value refund -- but only within 14 days of receipt.
In addition, Macs still available for sale as new are NOT eligible for trade-in.
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A the rate technology is advancing, Computers will always be faster, better, and cheaper if you wait.
But if you have work that needs to be done, at some point you have to stop waiting and select from among the best available at that moment and buy one.
When new computers are introduced (which they always will be) that does not mean that the one you selected and have been using becomes Trash. It only means an even better one was introduced AFTER you selected the best one for you at the time, and it may be at a similar price point to what you paid.
OK, next time you need a new computer, you will be able to do even better: Either better value for the same money, or more capable for a small amount more. What a great time to be alive!