There are a few reasons why you might need to rewire a house.
It is important to rewire your house if it has outlets with no grounding. An outlet without grounding is an outlet with 2 holes vs. 3 holes.
Cloth or Aluminum Wiring
You should also consider whole home rewiring if your house has cloth or aluminum wiring, which can cause a fire hazard, or after a major lightning strike.
Outdated Breaker Panel
A home older than 20 years with an outdated breaker panel may need to be rewired for a new updated breaker panel to suit modern electricity needs.
Unsafe or Poorly Installed Wiring
A home that has been wired unsafely should get rewired, because poorly-installed wiring can cause electrical fires.