I use Frontline + for flea/tick treatment..... once every 2-3 months (she is only outside for walks).
Interceptor once a month for heartworm... Chloe gets the regular de-worming once a year at the vets.
We use advantage plus that has the Flea and heartworm in it. We don't take Tuck where there are ticks so that hasn't been a problem. Our vet reguarly checks for worms and Tuch has never had a problem. Only problem we have with that is that every time the vet tries to get some fecal matter to check, Tuck is clean. We end up watching him for #2 and then take it into the vet. Not a fun job. Not quite as bad as picking up after him on a walk and discovering the bag has a hole in it and your a long ways from home so you can't wash your hands. Yuck.