I have 2 small breed dogs, one has never had an issue with her ears, the other one seems to have one every 5 minutes! I have an ear cleaning solution from the vet and that goes in every day or two and she shakes and rubs and then I wipe the excess that comes out away. She seems to produce more wax than the other dog. Now you know you can keep an eye on it.
I have never cleaned my dogs ears and he's a spaniel. I think it's probably one of those things that it's pot luck on whether your dog is susceptible or not (we suffer lots with allergies instead) so don't feel guilty.