"In 2004, Congresswoman Mary Bono resoundingly swept the 45th District Congressional election with a 67 percent majority, earning her fourth term in office. Congresswoman Bono was first elected to Congress in 1998, after a special election was held to fill the seat left vacant by her late husband, Sonny Bono. "
Call me cynical, but having actually campaigned for Mary Bono I don't have the highest opinion of her. Not that she is evil but she seemed to me to be a fairly dull fork. It appears that she does have a thing for attaching herself to bright, charismatic men though. That may be her primary asset. Lets face it, it Sonny hadn't died she wouldn't be anywhere near Congress.
I don't know if the word "earned" applies to any incumbent who is reelected. It is pretty much a given.
Other inheritors of congressional offices are Harold Ford, Jr., Jimmy Duncan of Eastern Tennessee, and of course, Al Gore. There are literally dozens of them from other states.