A lot depends on what part of the hiring process is slow. My general expectation is that the time between first phone call and final onsite interview will be 3

A lot depends on what part of the hiring process is slow. My general expectation is that the time between first phone call and final onsite interview will be 3 weeks at a minimum and 12 weeks max. After onsite, verbal notice should occur within a week although the actual offer may take much, much longer (annoying but expected in some organizations). The red flag is when you are told one thing and then another thing happens. In my experience that only happens about 100% of the time.