I'm asking question. If you have answer, please provide.
From this what I know, capacitors age only when USED.
No, all Amiga caps in all Amiga motherboards have well exceeded their life ratings.
Even if they are not leaking,they most likely have a reduced capacitance and/or may be completely bad.
These bad caps may not be filtering power coming in properly,or may allow noise or reduced volume on the audio etc.Dirty power can lead to random crashes and such.
Caps age mostly when not used.
It is why the military cycle their electronics often,to keep the caps viable, otherwise they go bad quicker.
Its a bit like letting a car battery set dead,if you leave it that way long enough it sulphates and/or shorts the plates and usually can't be revived.
old caps can leak and the leakage can eat traces just like the leaking batteries. I have repaired many boards in the last 15 years with neglected caps.
Its like having 4 bald tires on your car, and one blows out.. you don't put 1 new tire on knowing the other 3 are about to fail...well maybe you do,but most people dont lol