Seems like this year, fleas have been especially difficult for some pet owners this year... and even later into the winter than we usually see.
We had a good wet spring, summer, and fall, which probably helped their populations do better than during our normally droughty years.
There is not real silver bullet for flea control, but there are some tricks that will help!
1 - Treat inside, outside, and the pet at the same time! Otherwise you are just chasing the fleas around.
2 - Visit your vet for a good flea control medication. Generally, the over the counter and topical medications don't work as well as the newer oral flea medications.
3 - Vacuum inside like crazy! Studies have show that vacuumind and immediately dumping the canister will reduce fleas as much as 80% or more. That is a substantial reduction! Vacuum pet bedding, carpet, and ANYWHERE the pet rests, sleeps, or spends time.
4 - If you have fleas but no pet, use an Insect Growth Regulator like methoprene or pyriprofyfen. This keeps the eggs or larvae from becoming adults and reducing the population. You may not be able to control the stray animals or neighbors, but this will help reduce the flea populations over time.
5 - Treat today and again in 10-14 days. The first treatment doesn't often kill the eggs or pupae. 10-14 days is enough time to allow those eggs to hatch to larvae and pupae to adults and your second treatment will help really get them under control. Otherwise, all seems well for about a month and then they explode again.
As always, be sure to READ AND FOLLOW THE LABEL. Don't use products meant for outdoors in your home. Don't ever use off label. You can probably recall a terrible accident where a family died due to improper use of pesticides for fleas. Even things that seem harmless, like diatomaceous earth, should not be used inside if the label does not specifically state that it can be used indoors.