Are you talking about this website or the MLS? I do not know how often this website is updated. However, I can tell you that if you are looking at a website that is directly linked to the local MLS, you will receive more up to date information. My website is directly linked, so feel free to use it.
Guidelines for the MLS require that each agent update their listing within 72 hours of a status change. Most agents do follow those guidelines since we can be fined if our listing information is not up to date.
I hope this helps you. Please do not hesitate to call me if I can help you with other questions.