Elimination of all parasitic worms is basically impossible. What is done is the levels are managed. Rotational grazing is a key step, keeping goats on fresh, tall pasture that isn't full of manure, reducing egg ingestion. You've likely seen something called FAMACHA? That is a program used to...
Vets, like human doctors, need continuing education. Most vets will not recommended worming on a schedule. A few old school ones will. Up to date vets will give wormers based on the results of a fecal sample.
Worming should never be done on a schedule. Only as needed based on fecal exams showing a high enough parasite load. The practice of worming just because X amount of time passes is how resistance forms. That and underdosing or using the wrong wormer.
Current livestock evidence based medical...
You should always make sure any kind of worming agent is required before using it. A vet should analyze a fecal sample. You can either use your local vet, or send samples off for $5 per sample here, to Mid America Agricultural Research. It tells you what parasites are ailing your goats and the...