Just YES or NO is not sufficient for such question, You always need to support what you say. Such Interview Questions may have following Insights.
- To know if you are flexible enough to come on weekends to work if need be.
- To know how is your work style and planning and do you usually overrun schedule.
- Response should say that are flexible to come on weekends, holidays; work over time etc. whenever it is critical for the project.
- Make sure that overrunning the schedule is not a usual case for you because you plan better.
- Proactively you can also add what you will do, so that you do not have to face this situation often.
I will be ready to work on weekends or holidays if it is really critical for the project. However, generally, that is not the working style I would like to adopt. In my opinion, if the initial planning is done with care, such situations would not occur frequently. In my last project, we had similar issues in the schedule, after the first client delivery, we had team meeting to understand the schedule slippage and then corrective action of adding a domain of expert in the team who was missing initially to deal with the problem.
- Do not just say "yes" or "no". Elaborate.
- Never say that in my last project we have worked all weekends and holidays thinking that your hard work impress the interviewer.
- Just saying yes indicates you are gullible whereas saying no indicates your inflexibility.
- Interviewer would form an opinion that if you have to work all weekends for a longer duration, someting is wrong with you or previous organization you worked with.