Comment by rkagerer

It's also an investment of their time into you. I assume some candidates get cut after the first or second block, in which case keep in mind the further you make it, the more invested they are in you as a prospective hire.

It's important to remember the interview process isn't just one way. That's 9 hours you get to interview them (which I would personally love to help inform my decision) and you can always walk away early if it doesn't look like it will be a good fit.

I'd go even further if I could, and work on a little test project with the team to feel this out. Despite everyone's best intentions during a hiring process, neither of you know for certain how it'll go until you're in the trenches together.