In general, if something is not broken you shouldn’t fix it. A dog with hair in the ear canals but no sign of otitis (ear infection or inflammation) should not have the ear hair plucked.
Sometimes, plucking the hair from a healthy ear irritates and inflames the canal and could even predispose your pet to infection. Some cats have abundant hair growth on the inner surface of their ears but the ear canal is usually quite hairless. Cats do not need to have their ears plucked.
If your dog develops an ear infection, you may be advised to keep the ear canal free of abundant hair growth. In the presence of infection, excessive hair can prevent a desirable flow of air into the canal to promote healing of many ear infections. Hair can harbor the infectious agents and delay response to treatment. Ears can be plucked by a professional pet groomer or by you after careful instruction by your veterinarian. If you prefer, your veterinarian will gladly do this at periodic intervals if your pet is prone to ear problems. Plucking the fine hair from the canal is usually simple and painless. Be careful not to pinch the skin with whatever instrument you use (a tweezer will usually do the job well). If you suspect your pet already has an infected ear, ask your veterinarian to examine your pet before you intervene at home.