Electrolytics Question AGAIN

I have a Kenwood KA 8100 Integrated Amp which works great, however reading the forum has alerted me to replace the electrolytics in my unit. How do I know that it is really necessary to do this ???
What do I look for / or hear..if they are failing.
Since you have brought this up a few times already, I think you should have the caps replaced mainly for the peace of mind you will have. 
+1 stereo5
Rocky - The real problem is that they can fail suddenly and without warning.

So, the real question is, what would happen if they did? Can you find the replacement parts if they take out a bunch of output transistors, and would you afford it?

In theory, they could last another 20 years. They could also blow and take out a few parts. When that happens 100% you'll end up replacing all the electrolytics anyway, soooo....

They simply dry out.  Dry capacitor has increased ESR (equivalent series resistance)  resulting in poor control of the bass.

When ESR gets high capacitor gets hot from the current flowing thru it.  Increased temperature increases ESR even more and eventually it goes into thermal runaway (avalanche effect).  Before it happens though, capacitor will be at least very warm.  If it is cold and sound is OK then leave it.  Life of capacitor is in order of 50 years in normal ambient temperature, but each 10degC temp. increase cuts life of capacitor by 2.