TITLE: Presenting work in progress
QUESTION [26 upvotes]: At some point in the evolution of a project, one has to decide when to start talking about it in seminars and at conferences. I am interested in hearing about how other mathematicians make this decision. Of course the decision to give a talk on work in progress may depend on the state of the project, on the venue and the audience, and on other factors.
My specific questions are:

At what stage of a project do you consider it to be ready to talk about?
How does the venue (departmental seminar/colloquium/conference/other) affect your decision?  
What other factors do you consider when deciding whether to talk about work in progress?

I would be interested in hearing about relevant experiences that have informed your decision process, but please keep anecdotes anonymous.  Mainly I want to hear about people's criteria for evaluating when their work is ready to be publicly presented.

REPLY [4 votes]: (1) If I've thought carefully enough about a project that I have something to teach my audience by presenting what I know, I'll talk about it (qualifying the parts that I'm unsure of).  I prefer to give talks about what I'm most excited by at the moment; this isn't always what is most complete.
(2) The venue doesn't matter, but if there are fancy-pants mathematicians in the audience I will be more nervous about presenting partial results
(3) If I have something that is complete, that I'm excited about, and that will be new to the audience I'm talking to I'll usually choose that over something that is in progress.
Maybe I should be more worried about being scooped, but (a) I'm not presenting a proof of the Riemann Hypothesis (if I were it would be wrong) (b) Its hard to scoop someone based on a talk that they gave (c) Publish-or-perish pressure aside, most of the mathematicians that I've met are people of integrity (d) if someone uses my ideas to do something I might have done but haven't yet done this is a credit to my work (and moreso if they cite me).