A1354 was known as a 4th Generation AirPort Extreme 801.11n, introduced in October 2009 and discontinued in June 2011, so your AirPort is at least 9 years old and as much as 10+ depending on when it was placed into service.
The average useful life of most routers designed or home use is about 5-6 years, so you have had remarkably good luck with your AirPort. Frankly, the AirPort is living on borrowed time at this point, but there is certainly no harm in continuing to use the product as long as it meets your current needs.
Interestingly, Apple classifies this model as "Obsolete" as far as support status is concerned, which means that they will not help you with the product, even if you are willing to pay them.
The last firmware/security update for this model was offered by Apple about a year ago. Whether or not Apple will continue to offer updates is open to question.