Would like to suggest doing a worm count test for your animal, to see if they actually have worms and so you don’t have to load their bodies with poison. A lungworm test (and others) can also be done. Wormcount.com is a lab also used by vets.
Raw ground pumpkin seeds can be sprinkled on food to kill worms. There is a lot of info online. I wouldn’t use the pills, collars or drops provided by vets. Bad reactions can be had.
Those stupid monthly paid subscriptions is just a way to make money for the vets. There are alternative ways to protect from fleas, but cat fleas are the worst and dogs usually pick up those.
There is a lot of info out there re alternative flea treatment methods including essential oil sprays.