Yeah I've interviewed in Seattle and Chicago mostly. A couple half day visits sounds like a day's worth to me. :)

You're right I'm talking more like 4-6 hours... but at that point you need to schedule the entire day for it so you can be on time, leave room for extra time to talk if the employer wants, etc.

So again, it's not that it is exactly 8 hours, but that it pretty much takes up a day.