Many people think aluminum wiring is illegal, but in many houses this is what you find. Many (but not all) service companies will replace aluminum wiring with copper wiring. Some will not.

Many people also think any wiring from the pole and to the service meter are the responsibility of the utility company, but in many places this is not so. 

I also see that nobody even looks (when buying a home) at the wiring to and from the pole as many times it is in very, very poor condition to the point of being dangerous!

Wiring does loosen up over the years, and many electricians who know this re-tighten their service panel connections to assure the connections are tight.

YOU SHOULD TOO! - Ray