What's the nitty gritty of when quests are and are not offered?

[zanzibar]

If you have to drop a quest because of a bug, how do you know when to ask for that quest again?

Yesterday I accepted a bunch of quests from the bronze door region.  I found a conflict, so I discared the quest causing problems.  I found that the quest which I had just supposedly salvaged wasn't working anyway despite dropping the other quest.  A third quest also didn't work, and I have no clue why not.  A bunch of other quests were also dependant on other quests being solved first.  So I just dropped all the quests.  Now, I'm not being offered them, even though it's many hours later.

So, how will I know when to ask the NPCs for their quests again?

[Bartholin]

same thing happend with me with the merc helm quest.. didnt get it again till a week later.. so idk.. i think that a quest should only be offered if you can infact complete it.. so if a quest needs you to have done another quest.. then you cant do the quest untill you did the needed quest before hand.. it would just not be given to you.. but thats me