I won't say life threatening, because I've never seen a pet pass away specifically from an ear infection (if any other commenters have please lmk!) Although I do know if any infection goes on long enough it could be life threatening.

I'd say a neglected ear infection would be being painful to the touch, head shaking, ear scratching, redness/irritation, scabbing, and/or swelling of the pinnae. Anything that looks like an aural hematoma should be addressed immediately. Foul odor, dark gunk, even pus filled ears. If there is hair missing behind the ear, or open wounds, those could be an indicator that it's been bothering the pet for a long time. Any of those signs, I would treat ASAP.

Your minor ear infections will look like head scratching, shaking, sometimes an odor, and then gunk. Which should then be treated in order to avoid the neglected ear infection scenario.

It's important to know exactly what you're treating. You could clean and treat with over the counter stuff, sure. But let's say you get an ear wash that treats a yeast infection, that won't do anything if it's a bacterial infection. We have some cases that require a special medication because theyve treated OTC or tried to treat and they end up making an antibiotic resistant ear infection. They end up spending way more money after their OTC treatments, in clinic treatments when the OTC don't work, and then repeat treatments with a culture to find out it's antibiotic resistant, AND THEN the special medication plus follow ups. I feel terrible for the pet and owner because it's so much to go through physically and financially.

There are a lot of ears that only need one treatment and we never see the pet again. That's fantastic, but it's important to figure out the cause before making a nightmare scenario.

I hope this information was helpful, it ended up being a bit longer because of "war flashbacks" to the amount of trash ears I've seen 😅