Heartworm question

We have 3 shihtzu's, tons of cats (actually 5 but it seems like a ton). I work at Va Tech and one of our professors is a microbiologist who was formerly a vet in practice. Now a researcher at VT. He says the heartworm tablet is nothing but a waste of money and added meds that pets do not need. He says they only need the basic worm liquid that you get at any store or from the vet. He said they need the liquid wormer on a regular basis but our vet has NEVER given any of our pets liquid wormer since the first dose as a kitten/pup.

The high cost of vets is really getting out of hand. We gladly take in new babies that need feeding until old enough to be eating solids, etc. and then find excellent homes (or keep them :) ). He and others have said giving injections ourself, since I already do B12 injections to myself, that buying from a reliable pet supplier would be easy, cheap, and reliable for someone who has experience with injections. I believe Omaha....something is one of the companies he uses and recommends. He is also very willing to show me how to actually give the injections, etc. If you check online you'll see that 6 cats can benefit from the exact medicine that 1 will cost at the vet - and the only other thing they do is feel the cat....I can do that....duh.

Any thoughts out there? We are very good pet owners, all pets get regular shots, got for any illness, are loved more than most kids, and feel this would be a great option for us. I welcome any thoughts.....
Kathy