I Have Adult Children who think the world owes them! When ever they come over to visit they rummage through the house. They act very obnoxious,& selfish. My age 50,My Daughter is 26, My son 21. & I have two small grand children. I thought about moving farther away so the visits could be less frequent, but... Then I would miss them all. Does anyone have any suggestions?

Change the locks... and tell them what you told us... its YOUR house, and YOUR things... and if they can't respect it... they can't enter your house. You have to take a stand sometime before they will get the message.

And reinforce it with they will all be out of your will unless you can get the respect they owe you.

You can give it all to the Church if you want... or anyone else. That might get their attention.

Yes, tell them the rules, it is your house and your rules, if they are "looking around" ask them what they are looking for.
Ask them if they want you to come over and do the same at their home