Never. The world doesn't need more puppies
If you had done research, you would discover that one successfull mating is enough for a female to get pregnant.
I hope your dog is at least two years old, has her health certifications, and some form of title (either in a show ring, or as a working dog). And that the male has all the same things.
if not, she is a PET QUALITY dog. this doesn't mean she's not a good dog, it just means that she isn't going to bring anything good to her breed. The reason people who show their dogs breed them is to make the breed better and healthier. they don't just breed for the sake of making more of that breed.
I suggest getting her spayed. Unless you have at least $3000 for vet bills while your female is pregnant, and just in case something horrible happens involving the pregnancy.