I usually give a week for people to get their stuff together and then we all post about the same time. Everyone will post their pics 5/5-5/6 so it will be flooded with customs. It's the only way to keep some continuity when viewing the theme. It's no fun if you have to look every 5th or 7th picture for the theme. By giving everyone 1.5 weeks, it'll be a chance to do last minute customs or prepare those gnarly shots.