David Patterson taught me this valuable lesson:
When you are invited to travel in order to give a talk or similar:
(1) never respond immediately, certainly not during the same phone call.
(2) visualize the trip not 8 months in the future but next Monday, with all details, inconveniences, and uncertainties.
(3) ask the opinion of a cynical colleague (he named one but I will not): “should I accept?”
If after these steps you still want to go, then accept the invitation.
It has worked well for me…
When I was in my second year of PhD, I remember coming to Christos (Papadimitriou, my advisor) and telling him that while I was having fun working on 5 unrelated projects, I felt that I should focus on one concrete theme for my dissertation. I was wrong, I was told, “Don’t worry about your dissertation. Work on whatever you find interesting. If you work on something you’re excited about, you’ll do well eventually.” Christos denies ever having this conversation, but I still think it’s a great advice.