Many of the "facts" you "know" are really just useful anecdotes, opinions, approximations or mental shortcuts rather than objective facts. These can still be wildly useful, even if they aren't "true" in the pedantic sense...

As a basic example: Newton's laws aren't a fact. They're extremely useful approximations; to get a more-complete picture you need relativistic effects, quantum effects, etc.

As a rule of thumb: Fact check in proportion to the cost of a mistake.