system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5 Why people don't get sick from using the same toothbrush everyday without disinfecting it?

If I spit on something every day and then kept putting it in my mouth shouldn't I get sick?
gpt
The bacteria that are inside of you will still be the same bacteria that left you (toothbrush) and go back inside you (brushing teeth) again. It stands to reason that if they don't make you sick while they were inside you before, they shouldn't make you sick when they go back inside of you again.

Obviously, the same isn't true if you're using someone else's toothbrush.