I clean about a month before my hunts. Then shoot 10-20 rounds through it to foul the bore. One final 1 or 3 shots the weekend before my hunt.I have an honest question for the guys that dont clean "Until accuracy goes South". How do you know that your not going to find out your accuracy is degrading on that 700 yard shot at a trophy animal? That would be unlucky. I usually like to have a little more control over things that I can directly affect than "Guess I'll wait and see what happens".
But other than that, I go 100 to 600 rounds between cleanings. That could be a month or 6 months. But I also know about when accuracy is going to start falling off from experience.