Radio rebuild

Jim Kueneman said
Very few I have restored have needed anything but replacing the electrolyte caps that were dried out (especially the AGC cap) $5 and 30 minutes of time can bring a lot of these radios back to life.

Educate us. What can we look for in the future to get these Bendix 222 radios 1965 CircuiTrace Bendix Radio back up and running? Common cap fault areas?