My DD11s first number was previously assigned to some woman who owed a lot of money (collection calls) and who was still putting down the number on things like when she signed up to work charity events, stuff from the university etc. There were several such calls a week to DDs phone. Since she didn't have the phone except for when she was left home alone they all went to voicemal where they got deleted.
DH had a number that to this day is still out there on some Century 21 real estate signs. DH would get a couple of calls a week, sometimes a day. He even called Century 21 to let them know that they would have a hard time selling the properties with his number on them. Still they came.
When we switched services we changed both of their numbers.