Gargling daily with mouthwash can help prevent sore throats from occurring because the mouthwash will kill the bacteria that causes sore throats to occur.
The mouthwash will also prevent tooth decay, gum disease, gingivitis etc so not only will it prevent sore throats it will also keep your mouth and teeth healthy as well.
You can also prevent sore throats by gargling with apple cider vinegar and another benefit of gargling with apple cider vinegar is it's safe to swallow unlike mouthwash.
Apple Cider Vinegar is also good at killing bacteria in your mouth and is good for getting rid of sore throats when you have a sore throat.