if the situation isn't extremely bad (trust me, i've seem bad) a fogger is definitely your way to go. But i've been in situations where the fleas were just so bad a fogger barely did anything. i was cleaning out this ladies house who was a hoarder and for a whole year she had this house she didnt even live in but her three cats sure as hell did. and you know those cats made their way with all the furniture and carpet available. stunk to high heaven and one step in that house your legs instantly turn into a flea farm. we had to call an exterminator to de-flea the whole house.