Yeah, I felt I couldn't even vote because honestly it is more than once or twice per campaign (which spans months to years of actual game play) to every few sessions. You really needed a category in between IMO since that is where my vote would have gone. Too bad really.There's a huge gap between "once or twice per campaign" and "every few game sessions". I'll have a dragon* show up every now and then - maybe not every few sessions but way more often than once or twice per campaign (or I bloody hope so anyway, seeing as I tend to run 10+ year campaigns).
* - including the occasional decent one that isn't out to kill the PCs on sight and might even be talked into helping them out....
I would have to say maybe once or twice per tier of play is where our group lands.