We've been using PetFriendly monthly for over a year now and have remained flea free ever since! My cat is an indoor cat, however, we live in an old house in the middle of a hay field and do get mice and the occasional chipmunk that finds their way in here (yes- ugh)! These critters have introduced fleas in our home in the past, but without a host, they cannot survive and my cat can no longer be their host with PetFriendly's flea/tick preventative! It's very cost efficient and I've found it to be more effective than the expensive stuff we were using prior. Plus my cat LOVES the Bug Bites treats that come in every box! It definitely helps take the 'sting' away from mom applying her preventative each month. She now knows she will get a delicious treat after and no longer runs when she sees me get the preventative out. THANK YOU, PetFriendly!