At support.apple.com Apple has a list of obsolete devices. If you know the make and model of your Mac, you can check this comprehensive list to easily check if your Mac is obsolete.
If your Mac is not on the list, your Mac is not obsolete yet. If it is, then I recommend considering your options in the event that your Mac needs to be repaired. If you aren't positive of the make and model of your Mac (in particular, the year), then you can continue with this guide.
Click the Apple logo in the upper left-hand corner of your Mac.
Select "About This Mac."
Find the make and model of your Mac so that you can see if it is included with Apple's list of obsolete products from step one.
Now that you know the year of your Mac, compare it to Apple's list of obsolete products. If your device is on Apple's list, it's obsolete. If it isn't, your Mac is not yet obsolete.