When to file a bug, and when to use the list?

[Brian Bober]

I have a question about what is something we should present to the list only,
and when should we file a bug? Should we send the message to the list first and
then be told to file a bug, or should we do both, or should we just post to the
list?

Can you give examples of things that we should post the list instead of filing
a bug (and vice-versa) if you can think of any? Should we generally ask the
list about something that seems to be a bug, and if no suitable answer is found
in responses or the archives, and no bug is found, then file a bug? Or do
developers often see things on the list and file bugs on their own components?