Have you heard of Federal Pacific Electric? I was recently the listing agent for a house built in 1973 that was very well maintained. The home inspector noticed however that the main electric panel was made by Federal Pacific Electric. Come to find out, the company went out of business after a number of lawsuits against them for their breakers not tripping. If you google this company you will easily find more information. Most insurance companies recommend if not require replacement, and in the case of my Seller she had to credit the Buyer $2,000 for the cost of replacing the panel. Just one of those things that is good to know if you own an older home or are looking at buying one!