When you have a question, what is it? Is it an inquiry? is it required? Is it filling in a gap? Or is it a QUEST -- i.e. discovery, investigation, seeking. Are you just asking or do you really want to know? Even when we are seeking information as part of a job -- unless we "own the question" just like we "own the problem," then we will find less than optimal results.
Estimate the time it will take and estimate how much time you are willing to devote to it. What's the difference?