My vet is on the cautious side. He doesn't bombard with meds and hope one works. Baytril should be sufficient to kill what ails you, which is why it is prescribed often, when it didn't, he added ampicillin. That did the trick and we didn't have to pursue farther. I find it funny that they yell at vets for prescribing Baytril like aspirin, when we prescribe Cipro the same way. It has low side effects, is usually effective in a wide range of ailments, and cheap. What more could you ask for!!?? But to more answer your question, I don't know if he has a set game plan on usage of meds, like I said, he likes to try the least invasive and move up.