The good news is that most problems have to do with the initial installation and adequacy for current loads. Over time people tend to use more power in different locations. Which leads to overloaded circuits and the use of extension cords as a substitute for a proper installation. Both of these situations lead to problems and they account for many fires.

Barring this sort of thing the vast majority of acute problems in any electrical system will be where connections are made, junction boxes and panels; where wiring is exposed to wear and tear, receptacles and extension cords; and where it is mechanically damaged.

These sorts of issues are easily spotted by a diligent inspection by a well train and experienced electrician by inspecting the wiring that is accessible.

A careful visual and electrical check of the panels, opening a representative sample of outlets and switches, and a quick visual inspection of any exposed wiring in attic and crawl spaces can go a long way to determining the health of an electrical system.