well, i can't exactly give you the information you're asking for as i am no longer using knives in a pro kitchen. however, i have cooked professionally and now own 2 Katos so I'll go as far to make this observation:
The Katos have what I consider very good or above average edge retention. Many have said they thought they were superior to Shigs in ER but I'd say my experience places them pretty much even.
How long between sharpening? There's an insane amount of variables here. If i was still doing a lot of precise and detailed cutting of vegetables, I'd probably take the Katos to a finishing stone daily. In a 'standard' western kitchen where knife work is less frequent and less precise, you could probably go almost a week with care and a strong starting edge.