We have a 12 week old puppy. Have I missed the window of time to try and desensitize him to thunderstorms, fireworks etc? We have him 3 weeks now. During that time it has thundered on 3 occasions and fireworks over the New Year. He did OK but we gave him lots of treats and made it a fun time. I just bought some CDs with the noises and am wondering how often and how long to play them each day. One is Thunder storms and the other is Fireworks, should I alter them. Our previous collie developed SEVERE storm phobia at age 2 so we want to do everything we can to prevent that this time. It got to the point where even rain and dark clouds would start her panic attack.