This question is best asked at the end of the interview process. As you are nearing the point where you believe that the employer could soon be making you an offer. You can use this question to understand exactly when the company would expect you to answer.
Get to Next Level: This question is one way to get the process to move forward.
Show Interest: You can with this question signal your interest for this position.
Juggle Multiple Offers: If you are waiting to hear back from other opportunities or are evaluating multiple jobs, you can use this question to make sure that you will be able to inform others of what your selection process looks like.
Consider Cancellation Period: If you work in a country with longer cancelation period and want to return home, you may need to check that this is ok before you proceed. In most situations, a company should not have a problem waiting for the right candidate, so do not introduce this factor until you are further into the process or presented with an offer, unless they ask of course.
Could Signal Disinterest: Asking this question could be interpreted as not being interested. It can appear that you are evaluating other opportunities or waiting for feedback on other interviews before you have to answer here. However, perhaps this is true? If this is not your first choice, but you are still considering this opportunity, you need to make sure that you are still able to peruse your number one opportunities. Sometimes interviews can also reveal that this job is the best choice and not the one you were first interested in.
Asking it too early: If you ask this question too early in the process, it will most likely harm your chances at getting the job. You need to ensure that your timing is perfect for this position.
All Questions to Move the Process Forward during the job interview