Guild Wars 2

So, since I’m starting to get into soloing dungeons, I thought I’d ask this forum a few questions. Mainly, I’m confused about how the instance persists. Sometimes, it seems as though, while solo, I can log off and in with the instance staying where it was, but other times the instance is deleted. Could someone please clarify the mechanics behind dungeon instances? Thanks

You reset the instance if you log into another character, then back to the original character. I haven’t tried exiting the game completely, though.