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:

1. At what stage of a project do you consider it to be ready to talk about?
2. How does the venue (departmental seminar/colloquium/conference/other) affect your decision?
3. 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.