Some owners only have their horses done every other year but then their horses have more problems and discomfort when chewing.
I won't have mine done every year unless they indicate they need it. Both my boys are fat. Neither seems to have any issues chewing.
What do wild horses do? They don't get their teeth floated every year
I think this will be a three part answer:
1. For the most part wild (The Preswalski Horse) and feral horses tend to live in both dry and harsh country. They run toward smaller size, slower growth, high death rates. I would suspect the teeth, like the hooves, tend to be harder, smaller, rougher, but serviceable.
2. Such country is usually very dry and dusty and or sandy. The grit helps to smooth off their teeth as it's picked up in feeding.
3. During the harsher times, such as after the often single annual flush of soft grasses, they don't see another blade for a 50 weeks or so. That and winter leaves them browsing a great deal on harder brushy plants. More tooth wear.
There is a forth answer. They die either after their teeth become unusable and they starve, or they die at a younger age before teeth can reach that stage.
We did pretty well too, in the wild, without lots of things, but I think we suffered much the same fate as other creatures, such as the horse. A quite high death rate being the result. Not a lot of elderly among the prehistoric folks I think.
Some folks were discussing "slow feeding" tools on another forum (Equine Cushings Photo) and the issue of dusty hay and high hanging feed bags came up. Folks were worried about all that dust getting in their eyes, and maybe being breathed.
Two conditions horses have evolved for and I believe not dangerous really unless they are otherwise compromised say in their respiration processes.
And I can't remember when I've ever seen any hay derived particles in a horses eye and had to call the vet.
Finally, the dust serves their dental needs as it did their ancestors.
For myself, the stuff makes me sick for a day. Just like a bad cold if I get a big whiff of it. But then I'm allergic to lots of grass products, including most grass derived grains, cane sugar, and similar. In fact, I've got a stiff neck right now and swollen glands in the neck from moving too fast this morning with the hay transport. Got a nice shot of pollen and hayfield dust. They sure cut that batch low to the ground.
I am with you on the need before treatment mindset. Same with worming. I only worm if a fecal sample says I must. (Altea was clean as of last week's sample analysis ... looks like Bonnie will be for a long time as well then).
I'm the same about myself. Natural health maintenance when I can, see the doctor when I must. Where there is actually a need. Of course at my age ...