You submit a paper to a fancy journal. The journal acknowledges the submission, and informs you that the review process typically takes 6 months. You wait 6 months. Then you wait a few weeks more. Then you send an exceedingly polite note to the journal editor, registering a "friendly query" as to the status of the submission. You either get no reply, or you get a reply saying that the editor will "look into" the status (it matters not which). Another two weeks goes by. So you send another exceedingly polite email, now registering a "friendly query" concerning the editor's query into the status of your submission. More time slips by, and you get no response from the editor, or you get another "I'll look into it" note (this time more curt than the prior response). More time goes by....
And so on. Some questions: What can one do? At what point should one just retract the submission? At what point is one justified in sending the paper out to another journal without retracting from the first?