As long as it takes you to teach it. There's a sticky in this forum or the training forum called "The bite stops here". Read it and follow the advice. Be consistent and patient. It does take a few weeks for a puppy to catch on.
Don't be frightened by it. Play biting is totally normal and training bite inhibition does work if you put in the time and effort.
Also, if the puppy was taken from her littermates and mom before 8 weeks, it will take longer to teach bite inhibition. Normally, puppies learn a lot of bite inhibition between 6 and 8 weeks from each other. Keep in mind, a dog is covered in fur, so the same bite that hurts a human is harmless to a dog. It does take dogs some time to get the difference.
Don't be frightened by it. Play biting is totally normal and training bite inhibition does work if you put in the time and effort.
Also, if the puppy was taken from her littermates and mom before 8 weeks, it will take longer to teach bite inhibition. Normally, puppies learn a lot of bite inhibition between 6 and 8 weeks from each other. Keep in mind, a dog is covered in fur, so the same bite that hurts a human is harmless to a dog. It does take dogs some time to get the difference.