I worm my puppies at 2 weeks, 4 weeks, 6 weeks, 8 weeks, 12 weeks, then 6 months and every six months thereafter unless there is a specific reason such as a flea invasion or about to mate a bitch.
I use Panacur Liquid 10% for in whelp bitches and baby puppies, then Drontal Plus tablets for adults.
Much cheaper online than the vets, and the vets will tell you to do them every three months, but unless there is a specific reason such as fleas or eating lots of things like wild rabbits then there is no need.