Eight ever, nine never 

Definition

"Eight ever, nine never" is a designed to help the declarer who has eight or nine cards in a suit including the Ace and King and who is trying to decide whether or not to take a finesse and cannot afford to lose a trick in the suit. 'Eight Ever' means when you hold an 8 card fit in a suit you should always try for the finesse. 'Nine, Never' means that you should never chance a finesse with a 9 card fit you should instead play for the drop leading out your Ace and King hoping that the outstanding honor is in a singleton or doubleton and must be played.

The Odds

Faced with the decision between making a finesse or playing for 'the drop' declarer should look at his holding in the suit. The finesse always has a 50-50 chance of success, whereas playing for the drop with a 9 card suit has a slightly higher percentage success at 53%. The drop becomes more likely to succeed the more cards the declarer holds in the suit.

The Rules

With a nine card fit - leading out your Ace and King gives  a 3% better chance of success than playing for the finesse of the outstanding Queen honor card.

Solution

In the hand below try making the heart finesse and then redeal and play for the drop.