How accurate was Ron Howard’s Apollo 13?

This coming week marks the 25th anniversary of the release of Ron Howard's Apollo 13. Based on the book Lost Moon by astronaut Jim Lovell and author Jeffrey Kluger and starring Tom Hanks, Bill Paxton, Kevin Bacon, Gary Sinise and Ed Harris, it tells the true story of what many consider to be NASA's finest hour: the saving of Apollo 13. But just how accurate is it?