They aren't individually fused - which means that if one piece of equipment goes down it could take the whole circuit with it

This is a very common occurance in my house, considering it's age. The electrical system is a mess, and I still have no clue what outlets are on what circuit. The rule though right now is no cleaning at night, since usually whatever circuit so many of the plugs are on can't take the lights, and a vaccum cleaner. The best was when I took out the trash, turning on the back porch light, and left two friends in the basement in pitch blackness.