For casual stuff like walking through a forest or chatting in a tavern, I say we should post within at least a week from our last post. Of course we can post more than that within a week, but the maximum players should wait if they're looking to respond to a play is a week, unless otherwise forewarn.

For combat where things are more intense and fast-pace, three days tops. I understand that people can be busy, get writer's block, or just straight up forget, so 24 hours seems a bit too harsh considering we can't dedicate all our time to RPing. At least 3 days and maybe dropping a mention in the relevant post directed those PC's whom the actions of a player or enemy would directly affect (i.e. mention me if you're about to have the dragon eat my character).