I like it early in blitz when playing as white and queen side castle is open and d file is open.
Qxd8 KxQ the swap
O-O-O check
Advantage, tempo plus king safety plus rook controls file plus black King loses castle privilege plus black rook (A8) will never get out. I'll take that swap any day.
Well, I do it a lot in blitz because I blunder so much. I figure that at least this way I'm making sure not to give her up for free :)
But that's just the last of my reasons. If I can think of a good reason to keep or trade the queen, then I do that. If it seems the same either way, goodbye queens.
Blitz is a battle of instincts and what you already know. To get better you need to analyze your games and especially play slower games so you could forge your safety checks into insticts (i.e., naturally not hang stuff or concede major positional concessions like instinctually preventing a Ne6 outpost by our opponent or easily exploited backward pawn on an open file).