We have Jess on Advantage against heartworm, apparently there is quite a bit of it around where we are, and also she has Billy No Mates once a day because Advantage doesn't do anything re ticks. BNM is a herbal mixture, it smells spicy, and it is supposed to repel ticks as well as fleas and mites, anyway so far so good because we have not seen a single tick. Also it is supposed to be good for the coat. Jess certainly loves it.
We do still have the OTom though just in case.