Since I now have 3 cats(who do not go outside) and 3 dogs(who do go outside-just to potty). I need to make sure no flea infestation occurs and to try and do it with the least money. My daughter bought Hartz product-haven't used it yet. Have Frontline- that has been my standard for years but is much more expensive than Hartz. Want to start the season with one and cont. with it. Did not like Advantage-did not work on my largest cat(Kitzel 15 lbs.). Long ago one anti tick-anti flea stuff caused renal failure in my friend's dog. Thanks for any information. I want to keep all my 4-legged babies healthy for many, many years.