How many days should be the allowance days before reapplying if i am denied to get a visa

Hi there, i have a schedule to go to china as a tourist on oct.3-26 2014, and my passport will expire on march 12, 2015. If ever I apply on my old passport can i still use that if i renew my passport? Or its just ok that i use my old passport with its march 2015 expiry? Also how many days should i wait before i can reapply for another one if i were to be denied?