This is one of the favorite tough questions, co-founder of Interview Circuit. It's tricky because "I don't have an answer in mind when I ask it," he says, "and I use it to see how the candidate reacts."

A variety of answers would be acceptable in this scenario. "A good answer would be, 'I'm willing to stick with this job for as long as it takes to succeed,'" This shows endurance and that you're in it for the long-haul.

Alternatively, you could say that you plan to fail as quickly as possible so that you can learn from your mistakes and move on. "That answer would indicate that they're impatient, aggressive, and not afraid to fail (which are things I like),"

Bad answer: "A few months, or I don't know … what do you think?"