Depends on the podcast and the users. If I know my favorite afternoon commute podcast drops at 4:30 PM local and I don't see it by 4:45 PM, I'm going to be doing the pull-to-refresh thing frequently, hoping it's available to download before I leave the WiFi at work for my drive home. I suppose Podping plus push notification to all app installs subscribed to the podcast that just updated would be another way to do it.
