Mail message delete preferences don't work and all the messages about this are 12 years old. I have to delete messages manually from both my junk and trash folders.

I use Apple Mail and POP3 Mail server. I have set my preferences so that Mail should remove items from the junk folder after one day and from the trash folder after one week. THIS DOESN'T HAPPEN. I have to remove the messages manually, which does work, thankfully.

All the help about this same problem I could find took place in 2006 so I don't trust any of the solutions offered.

I am using the latest version of OSX.

How can I (or Apple?) fix this problem