Unless you want to show the dog, cropping is not necessary. It's been banned in several European countries, and talk is that it may be dropped as a show requirement here. Potential problems include a bad crop,(too short or long), uneven ears (one stands different from the other giving the dog a lop sided look), and also increased need for cleaning. Prick eared dogs generally need to have their ears cleaned out more frequently. A good crop looks nice, but there are risks.