Luke 8: Telling others - What's the difference between Jesus driving out demons & healing Jairus's daughter In Luke 8, the man freed from the Legion demons is told by Jesus not to follow him, but to tell everyone round about. But later, Jesus heals Jairus's daughter and tells the family not to tell anyone. Why would Jesus want the man who had demons driven out of him to tell everyone, but not want Jairus's family to tell everyone about the miracle?
The difference is that, in the pigs story, Jesus was asked to leave the region:


  Then all the people of the region of the Gerasenes asked Jesus to leave them, because they were overcome with fear. So he got into the boat and left. 


Luke 8:37

So the formerly demon possessed man was possibly the only witness / preacher / disciple Jesus had in the region.

In other cases, Jesus' popularity has prevented Him preaching (Mark1:44-45) and even eating (Mark 6:31)! So He often told people not to tell others about the miracles.