My take on this is a little preventative work goes a long way... Take the top off and clean everything with a vacuum and acid brush plus blow it out with compressed air, why?? Heat is your enemy and thats what causes heat fatigue on caps and soldier joints (look for darkened spots on your PCB's. If it's running primarily in class A, get a six inch (computer type) fan and cool it...
Preventive maintenance or wait till it breaks?
This is more focused on older gear- do you run gear until it's showing obvious signs of problems or do you do preventive maintenance before problems appear? I fall into the preventive maintenance side as I replace capacitors that are 20 or more years old.