I have been using my Brickwall AUD15 for some time, geeeze 9 years at least. It's excellent. Well worth the $250.
I asked the question of capacitors replacement on a used unit this was the reply I received:
"The units are guaranteed for ten years because that is the minimum life of the capacitors. It has been our experience that they generally last much longer (like 5 to 10 years longer).. Also if the capacitors happen to fail, it doesn't stop working as a surge protector... it becomes a surge protector with a slightly larger let-through voltage. If you are still not sure you can send the unit in for testing. If there is a problem we will charge you the cost of fixing it.. Hope that answered your question.
Ryan Cox
Sales Technician"