I had 6 Long interviews for relevant jobs and they all took at least 2-4 hrs each time. In some of these interviews I had to meet with multiple teams that actually would not even be my direct coworkers in order to see if i was a good fit. Needless to say I ended up getting a different job 6 months later and was hired over the phone without a onsite interview

Three part process, with a phone screen and take home. Talked with two engineers and hiring manager. Lots of physics questions and overview on projects done. Many steps and overall good experience.