I have been using heartgard plus for heartworm prevention and comfortis for fleas. I used to use frontline plus but it doesn't work very well. It wouldn't even last a month sometimes. I have been using comfortis for 6 months now and it works great. I haven't seen 1 flea since I started using it. I bought it for my mom and grandparents to give to their babies and they are both very pleased. I just found out about sentinel and I like the idea of just one pill to take care of the heartworm and flea prevention plus it protects against other worms also. Comfortis was between $60-$70 for 6 months and I usually pay about $20 for 6 months of heartgard. I have found Sentinel for around $60 for 6 months so it will save money if it works. Try
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