I have never owned a tube of toothpaste long enough for it to expire. But I bought four tubes a couple of years ago, and it has taken me this long to get through three of them.
I didn’t even know toothpaste could expire, so I was surprised when I opened tube number four to see its contents had turned into a slimy liquid which, while retaining its minty aroma, had lost all of its paste-like qualities. That’s when I examined the tube to see it had an expiration date stamped into it, and read online that after that date, the fluoride loses its effectiveness.
So, I have packaged the bad toothpaste tube and sent it off to Robert F. Kennedy Jr., who will no doubt keep using it until every last drop has been squeezed out.