
We wormed our puppies at 2 weeks, using a gentle worming syrup. Then every 2 weeks to the time they go home, with a full worming history, when and with what, and a recommendation they are rewormed at 3 months. After that, it's up to the owner. My bitches were all wormed prior to being mated.
Personally I don't believe in loads of worming - it's putting a chemical into a dog which may or may not, be necessary. I prefer to run a fecal, once the dog is through the baby puppy stages, before worming, so I know what needs to be done.