I just switched Bingo from the daily Filaribits ( I know, I 'm kinda old school!) to the monthly Heartguard Plus. I'm quite happy with it, considering Bingo was getting pretty fussy about taking his daily tablets. I was worried about all that medicine at once and about freaked when I saw the size of the pill i needed to give him, but he was maybe low for one day, if that, then was fine with it. I was REALLY happy to not have any side effects from it and it sure is easier to give once a day. THe only thing I don't like is that they can actually GET heartworm but it just in a sense kills them when you give them the tablet.....i guess it's just a mind thing you know? I too was wondering about the new shots that last 6 months and I'm sure with time that will be the new thing. Seems like a good idea but I've heard from a vet that is on the local tv station at noon that it's better to wait a while and see how it goes, than go right to it because it is so new....what do you all think about that? ....p.s. i think that boxer on the ad for it is sooo cute!!!!!