Safety or Maximum Tricks?
At teams, choose the line that makes the contract most often. At pairs, ask whether the extra trick or the safe contract wins more matchpoints.
Many hands offer a choice between a line that guarantees the contract and a line that makes more tricks most of the time. The right choice depends on the scoring and on what other players will do.
What a safety play looks like
A safety play gives up a possible overtrick to protect the contract against a bad break. For example, you might duck an early round of a long suit, or cash one honour before taking a finesse, so that a 4-1 or 5-0 break no longer beats you. When the suit breaks normally, the safety play costs you one trick; when it breaks badly, it saves the contract.
At teams
Take the safety play. An overtrick is worth about 1 IMP; going down in a game can cost 10 or more.
At pairs
Think about the field:
If most pairs will be in your contract, overtricks matter. Play for the maximum unless the safety play costs very little.
If you are in a good contract that others will miss (a game or slam others won't bid, or a better strain), just make it. You are already ahead of the field.
If you are in a poor contract, you may need a risky line to catch up.
Key takeaways
At teams, make the contract.
At pairs, consider what the rest of the room will score.
A good contract needs only to be made; a normal one needs overtricks.