You may have heard about infamous capacitor plague problem, where crappily manufactured capacitors died prematurely on people’s motherboards. Even if the capacitor was properly made, they still only have a finite lifespan, typically 10,000-100,000 hours. After this, you need to replace the caps or replace the whole board. This video shows you what to do! Some people also like to buy old audio amplifiers and are able to repair them simply by replacing the old, leaky capacitors with new ones. The same principles apply.