When to say "No"

Chase Jarvis has some good advice on his blog:
http://www.chasejarvis.com/blog/say-no-unless-a-project-has-at-least-2-of-these-3-things/

My own framework for evaluating a project is pretty straightforward but has proven very effective for my professional development and my career. Here’s my not-so-secret sauce: if it doesn’t have at least 2 of the following 3 components, my answer is “thanks, but no thanks”