not EVERY pet gets parasites nor does every human. Usually, dogs dont have much of a problem as their intestinal tract is much shorter than a humans, so anything they may have picked up ends up passing right through them quickly before it has time to hatch-- unless the dog has constipation issues as some dogs do.
If your dog is the type that rolls around in dead deer carcasses, and eats raw meat laying around outside-- and also eats rabbit feces-- then i'd err on the side of caution and give him/her some periodic dewormer every so many months. Our dogs do this , and we live in a rural area.
If you give them herbal dewormer they dont get the side effects that they would from the drug types (which are also effective)
I would use the Veternarian perscribed drug dewormer on pups that havnt been dewormed yet- and then the natural herbal varieties on older dogs.
I think its dumb to get rid of a family pet from paranoia over parasites.