When to let it go?

I decided to take this question to its own thread.



When you have a quality PSU, when do you take it out of service?



Mine are Seasonic, with 7 year warranties. But one Seasonic is branded Antec, and will hit the end of its 5 year warranty this year. There are other units of comparable or better quality, of course. So I want to ask a general question about all of them.



I have been told that good units don't fail bad and burn up other components in a system. But I have been reading about parts degrading with time. Does this mean that ripple and electric noise could increase?



So, the basic question is: prospectively replace a good unit (not junk or mediocre) at some point? Or use it until it dies?

When to let it go?