I'm always cautious about how much to respond to these discussions. There's a fine line between commenting and giving medical advice. The former is ok, the latter would be unethical.
That said, I'll make a few comments.
First, dogs don't just "get" ear infections, and to quote one of the dermatology lectures I've attended, there are three causes: allergies, allergies and allergies. That means that there will be flare ups, so my goal is always to decrease the frequency and severity, hopefully providing the owner with tools and a plan for managing the minor ones without requiring the time and expense of my involvement.
Secondly, while I see several of these per week, and sometimes per day, I haven't used oral antibiotics for years. You can't get a high enough concentration of the antibiotic without putting it in the ear itself. Steroids are another matter, but used chronically and/or repeatedly, can result in a lot bigger problems. That includes the topical steroids in the ear medications.
I see a lot of dogs with recurring otitis, and one of the most important parts of managing them is how you deal with the ears when they're not infected. These dogs need the ears cleaned twice weekly with a therapeutic cleaner. Ear cleaners from the pet store or some random pet supply website aren't going to suffice. Daily cleaning will cause the skin to dry out and crack, but a few consecutive days may be enough to settle a low level relapse. You've got to have the right product though.
Technique makes a difference also. I don't squirt the ear cleaner straight from the bottle into the ear. It's uncomfortable for the dog, which makes it harder for both of you. I saturate a cotton ball, and stuff the cotton ball down in the ear. The dog ear canal is like a funnel with a bend in it, you can't get the cotton ball stuck unless you're really determined. Massage the ear for several seconds, then pull the cotton ball out.
Unless you live in the desert where fleas can't survive, keep all of the pets in the home on an effective flea control product. That most definitely includes indoor cats. Fleas don't cause otitis, but any source of inflammation will worsen the problem.
veterinary partner.com is a good resource.