Here's a site I got this tidbit from....

http://www.pet-experts.com/html/buying_a_dog.html

Worming
Internal and external parasites can also be a common problem. It is important to worm your puppy every two weeks from the age of two weeks until twelve weeks. After which time the puppy can be wormed quarterly. ****Dogs should be wormed against tapeworm and roundworm on a quarterly basis.**** Symptoms of worms can include the following: rice-like segments in your dog's faeces, increased appetite, weight loss, scooting (rubbing bottom along ground), diarrhoea, vomiting and in extreme cases anaemia.

That's nuts, I'll have to call my vet in Texas and ask why she never told me about this. But, I do know, too, that she is of the opinion that we over-vaccinate our pets anyway. Maybe that's why she didn't tell me about it. But, no other vet that I've taken a dog to has told me that, either. So weird!