[trcollinson]

Two thoughts. First, if your startup requires people to give up nights and weekends and you need to ask potential candidates how they will mitigate that situation with their family life, then you need to rethink how your business and software development run. Work life balance is exceptionally important and should not be ruined for the sake of building a business. I realize you didn't bring up the question about giving up nights and weekends. But since the poster above you did, I thought it important that I bring up that requirements like that are absolutely absurd. If you regularly take away peoples personal time for your business, rethink how you run a business.

Second, on to your question. I have hired quite a lot of people and occasionally they are amazing in interviews and on paper and don't work out in real world situations. Over time you get better at spotting these people but it is a risk you take. As with many things, interviewing is a skill and some people are quite good at it. Often times it is not a technical or job skill mismatch, it is a personality or a team fit match. That can take weeks or months to uncover. The best thing to do is to have a clear exit strategy for each person you bring in if they don't seem to work out.