Sorry I dont want to keep going on about this like a dog with a bone but there is no risk to using regular wormcounts due to the life cycle of the worms. This is in reposonse to LandofGiants comment.
PollyRoulson's approach of using anti-parasite treatment based on need, makes sense and has potential benefit both to your dog and the environment. The drawback is the risk of the dog occasionally picking up a parasite.
You will not pick up any worms if you worm count as frequently as you worm there is no drawback. Advantages not giving chemicals when not needed and when they are needed given specific treatment for the worms that are present. Advantages to the environment and the prevention of chemical intolerance to parasites.
Nexguard Spectra which is treatment for lungworm give a 94% reduction of adult lungworm (figures from their data) so may reduce the burden in the dog but your dog could still have lungworm.
Nexguard themselves state that keeps lungworm under control and not eradicate lungworm.
I would argue you would get more protection from wormcounts.
Just for the record I am not anti vaccinations or treatment far from it and would never ever risk the health of my dogs. But over the years seeing the increase in medication needed for my livestock and the dogs and the environmental impact on unnecessary medication we need to look for sensible alternatives.
I am not evern trying to encourage anyone to use wormcounts but just want the correct information out there for people to make an informed choice.