Seasonic X660 degradation

Greetings everyone,



I have a rather specific questions and I've heard that this forum might be the best place to ask them.



3 years ago I bought Seasonic X660 (SS-660KM) from one local store and it served me really well over those years until it suddenly stopped working. Since it has 5 year warranty I returned it to the store for repair/replacement. Three months have passed since it was sent to authorized repair center and during that period I did not receive any info from them. After couple of unsuccessful tries to contact them and get some info about what's going on, I've finally decided to sue them in order to get my money back. Legal dispute has been going on for a bit, and in light of all evidence that undeniably proves I'm right, they've come up with the idea that since I've used X660 for 3 years, it is now degraded by 80%(!?) and they should pay me only 20% of my money.



That claim seems unreasonable to me and they didn't provide any proof whatsoever, so my question is - can X660 really degrade that much for only 3 years?



Computer in which X660 was used is my main rig built mostly for web design work: i5-3570K (not overclocked), 2x4GB DDR3, integrated Intel HD graphics, Asus ATX motherboard with no expansion cards, one SSD for system and one HDD for data. Everything assembled in CM Storm Enforcer case and cooled by two 140mm and three 120mm Noctua fans for silent and efficient cooling.



With this specs above, what is estimated degradation of that power supply if PC was used ~12h/day for 3 years?



I know there is no exact way to tell these things, neither they can prove it degraded that much, but I want to have at least some valid statements regarding power supply usage and degradation when I confront them in court.



Any valuable information is really appreciated. Thanks in advance.

Seasonic X660 degradation