Q: My Airport extreme and Time Cap. both only lasted 14 months, what's up with that. Time to switch brands?

Your Apple router is covered by Applecare extended warranty on a computer, an ipad or apple TV.

The program is fairly generous.. in that you can buy an apple TV now (Gen3 is fine) and buy apple care on it which is cheap. It covers any airport purchased up to 2 years earlier. So take your faulty AE to the apple store.. buy Apple TV and its applecare.. do not open the Apple TV.. get your AE replaced.. Then get a refund on your Apple TV. It is slightly devious but it is only if you do not already have applecare..

In EU or many other countries.. there are  statutory warranty provisions in your consumer laws that Apple must comply with.. And 14months lifespan is not good enough.

There are lots of issues with the current series of AE and TC.

Wireless continually failing.. power supply failures.

My first TC was like yours.. not quite DOA, but it was faulty out of the box and lasted a week total.

Second one was poor wireless. My older Gen5 AE and Gen4 TC were much faster.

Third go has been fine. (At least to this point).

If you want something better look at the top selections from here. You will find the AE in the list.. a long long way down.

http://www.smallnetbuilder.com/tools/charts/router/bar/113-5-ghz-dn-c

Airport utility says it may be overheating? How do you get that? Does it pop up under status when you click on the dot? I would like to monitor things like the temperature and fan speed but I do not know if that is possible. It is frustrating that Apple is restricting us more and more.

Where do you physically place the devices? If you place them in a warm space (high spot in room, enclosed cabinet,…) their life will decrease. For some reason, Apple decided to put the power supply in the units (instead of a brick power adapter) which adds heat. There is a fan in the latest units that suck and blow air out the bottom, if you block the tiny vents at the bottom the units will overheat. I have thought about adding an auxiliary fan to cool my unit, your post may motivate me. It would blow just on the outside of it but that can make all the difference. Had apple designed them to suck air from the bottom and vent it out the top, I would add an small external fan to blow into the bottom, but alas, that isn't how they were designed.

If you can manage applecare get apple to replace it.. it is their problem due to poor manufacture after all.

But if you need to fix it then yes, open it and replace the fan.. it might be cause just by dust clogging the fan and cooling vents.. which are very narrow in the base.