when i have made and sent a site over to somewhere like gaydemon.com how often do i need to update that site to keep it listed in the directory and making sales from gaydemon?

should i do updates every week or do you think every month will be good enough for a simple freebie site with maybe 40 or so pictures on it im thinking i could add 10 or more new pictures every month to my freebie sites and that will work good enough