I had about 6 interviews in total but I felt it was essential. It wasn't solely just my hiring manager but I had interviews with the team's overall lead and my peers.

The interview lasted 6 hours. I spoke with the person who was hiring, then went through different people with different job titles for additional interviews. The last person I spoke to was supposed to be an impartial interviewer but their job was not in any way related to what I was interviewing for. While I understand this is their standard procedures, it was a long tedious day full of repetitive questions.