Lungworm. A strange one this. Although we knew of a small area in the west of England, that was pretty much it. Then one of the wormers got licensed for the treatment of it, went on a huge advertising campaign, and all of a sudden it was big news!
Back when I started in dogs in 1955 it was the day of the latchkey dogs, dogs let out to wander the streets, only going home to feed and sleep. Nobody ever cleared up after their dogs, so worms tended to get spread around. But these were the normal worms, occasionally round worms, but mainly tape worms. My first dog did occasionally get tape worm which we found when clearing up our lawn. When we did find any we would dose him up and that was that. No continual dosing, just when we saw a worm.
By the time of my second dog the roads had got too busy for latchkey dogs, and the footpaths were much cleaner. I dont think I ever wormed him at all. The only problem we did get was the occasional flea. At that time we had many hedgehogs in the garden. So we did keep some flea spray around. (This was before the days of the spot on treatments.) But again we only used it as required.
After him came the start of my Labradors. It must have been my second, or maybe my third who started to develop a gippy tummy, so I wormed her, just in case. That must have been around 1980, and I've not needed to worm a dog since. As to flea treatment, yes, very occasionally I've needed to, but it's got less and less, coinciding with less hedgehogs seen around here, to the extent that in the case of my last three dogs I have only needed to flea treat once.
Modern wormers and flea treatments are powerful stuff and I simply dont believe in piling chemicals on my dogs simply on the off chance. I have never routinely used them and have never, after 70 years in dogs, needed too. Yes of course the manufacturers want you to, and so do vets. It's money in the bank for them. But is it really in the best interest of your dogs? I dont think so.