I have not had much luck with topicals. I have used Capstar and been happy with quick results, though fleas don’t STAY gone. Pill form at Walmart, says it can even be given daily.
Trifexis, prescription only, the special (no Ivermectin) heartworm I use with our Shelty, does a good job deflecting fleas, lasts almost the full 30 days between pills. I go to the local Pets Plus Vet visit, get the meds from them.
I need to apply flea-grub-tick killer to my outside dirt now. I have done that in the past and found it helpful. We just got a new septic system with new dirt, so it needs treating again. I believe the stuff is aTriazanine (sp). You put it in the fertilizer spreader and spread it around the dog areas, lawn, any bare areas and doghouses. We have a big fenced yard, so it gets spread all over.
I also wash the dog bedding often, spray around the crates, and bug bomb the house after plants and animals are removed. Then a second bug bomb 2 weeks later to kill any newly hatched bugs and break the reproductive cycle. Dogs and cats are washed with flea soap to be sure they are clean. I don’t seem to have any fleas after that, dogs and cats are checked often for fleas to prevent them getting started again.
I have no carpets downstairs, dogs not allowed upstairs. Cats not allowed in bedrooms (2) with carpets upstairs. Throw rugs get washed weekly, prevents flea eggs from hatching.
Sounds like a lot of work, but actually easy to do, along with weekly sweeping and cleanup. I use a steam mop on my vinyl floors, which cleans and kills any eggs. I HATE fleas, cannot tolerate them, so I work to keep them gone.