I also wonder how quickly does it take for a cavity to form realistically- will just forgetting once do it if you eat something sweat, sticky and sugary and forget to brush or drink water? My dentist told me once as long as you drink some water after eating something that's bad for your teeth- you will be okay and not get a cavity. (Provided I guess a piece doesn't get stuck in there and you just leave it and not remove it with floss out of laziness)

I used to be a bit worse than this but now I pay attention closer to my body signals and if my teeth feel funky, I take care of them.