Well, theres nothing to say there is a deadline. But I had incomplete documents for a couple of months sitting there, so they sent me a request for further information message, which then asked me to respond within 28 days. This is fair enough, I'm sure many people do the same and have to be prompted. I probably shouldn't have started the process so early until I had my documents ready, but then I had a deadline to apply due to state nomination. Bottome line is be as prepared as you can