Personally I find 20 to 30 minute interviews the sweet spot. Sometimes I’ll go a bit shorter and sometimes a bit longer but for 1:1 something like an hour feels too much most of the time.
I like the long conversations, because it’s easier to be a fake person for 30 minutes, but comparatively it’s hard to fake being a genuine person or expert on a topic for 2 or 3 hours.
I'm sure it's a fault of my attention span but I tend to be a fan of 30 minute conference presentations and otherwise distilling topics down to about that length. Otherwise, it often feels like you're dragging things out. I'm not having a date with the person. I want to discover for my audience what key insights they have.
I do sometimes have longer podcast conversations with people I know well but 20-30 minutes feels like the natural sweet spot for my typical interview.