Hi! I don't think an established posting speed or expectation was ever written...

My personal preference would be to check back daily, or perhaps, whenever you get a decent chunk of free time. Typically pbp games can update once a day, or every 2-3 days if they are "quick".

However, we players can post more quickly amongst ourselves, which is what might typically happen when one of our characters starts interacting with another. It kind of simulates actually having a conversation, you know? But that's only up to a certain point. It's good to allow others a chance to interact, too, in case a few people get carried away...