Here’s a scenario for flushing your job prospects away: the interview’s going great, the hiring manager seems to enjoy your work, there’s real interest on both parties, but then “Gosh I’d love to meet the president of the company, but my baby-sitter is only able to stay until 5 p.m.”
Treat your interview like it’s the only thing that matters in life, because right then it is. Don’t be worrying about time constraints. Just clear your schedule so you can put all your attention on the interview. Not only is watching the clock rude, but it also means you’re not going to be 100 percent for the interview. Plus, if the interview runs long, that’s usually a good thing, because they’re interested in you.