For 8 years I didn’t brush my teeth out of laziness. I drank carbonated drinks and ate candy like usually (which, as my weight would suggest, was too much). I have at present had three teeth pulled and at least three gaping holes in existing teeth. Beside the holes I also have calcified plague on my teeth which is where bacteria wants to live.
The holes don’t always hurt. Not always. But the pain they bring (when bacteria gnaw in the nerve) is excruciating.
Many animals don’t have the same access to sugar and acid as we do. Sugar and acid (carbonated water, juice) really takes a toll on your teeth.
Brush your teeth. I do now twice a day, but it’s too late to save them all.
(I answered anonymously because I’m too embarrassed to leave my name at the top of this answer.)