To use or not to use e-lytes is a personal decision one based on what is best for the horse, not what everyone else is doing, I hope.
I'm guessing that most of the lyte-less riders are in the west, where the climate is drier, or northeast where it is cooler (compared to where I live). My guess is that most central region and southern region riders will use elytes. The heat and humidity are killers.
As far as elytes being caustic, I don't think so. My horse Star has literally grabbed chunks of PerformnWin out of my hands and gobbled it down before I could get it in a syringe. Apparently, he knew what he needed and went for it.
I've gone out to my pasture on hot humid days and offered some elyte powder and the horses have licked it out of my hands and come back for more, so my guess is it wasn't that caustic to them or they surely wouldn't have come back for seconds.
I have seen vets here at rides administer some Lyte Now to horses that were on the verge of trouble and seen with my own eyes, the horses perk back up.
Does every horse in every ride need electrolytes? Probably not. But it's also not a good idea to say that no horse needs them. I think it depends tremendously on the conditions in which the horse is being ridden and the amount of energy the horse has to expend.
chris
I am not afraid of storms, for I am learning how to sail my ship. Louisa May Alcott