Rule #1 is also - "Never Screw (over) your partner.
Rule #1: Never let suspects stay together. (Yankee White, 1.01)
Rule #1: Never screw (over) your partner. (Blowback, 4.14)
Rule #2: Always wear gloves at a crime scene. (Yankee White, 1.01)
Rule #3: Don’t believe what you’re told. Double check. (Yankee White, 1.01)
Rule #3: Never be unreachable. (Deception, 3.13)
Rule #4: If you have a secret, the best thing is to keep it to yourself. The second-best is to tell one other person if you must. There is no third-best. (Blowback, 4.14)
Rule #6: Never apologize. It’s a sign of weakness. (Flesh and Blood, 7.12)
Rule #7: Always be specific when you lie. (Reveille, 1.23)
Rule #8: Never take anything for granted. (Probie, 3.10)
Rule #9: Never go anywhere without a knife. (One Shot, One Kill, 1.13)
Rule #10: Never get personally involved in a case. (Obsession, 7.21)
Rule #11: When the job is done, walk away. (Semper Fidelis, 6.24)
Rule #12: Never date a co-worker. (Enigma, 1.15)
Rule #13 Never, ever involve lawyers. (Collateral Damage, 6.07)
Rule #15: Always work as a team. (Leap of Faith, 5.05)
Rule #18: It’s better to seek forgiveness than ask permission. (Silver War, 3.04)
Rule #22: Never, ever interrupt Gibbs in interrogation. (Smoked, 4.10)
Rule #23: Never mess with a Marine’s coffee. (Forced Entry, 2.09)
Rule #27: There are two ways to follow: 1st way they never notice you; 2nd way they only notice you. (Jack Knife, 7.15)
Rule #38: Your case, your lead. (Bounce, 6.16)
Rule #39: There is no such thing as coincidence. (Obsession, 7.21)
Rule #40: If it seems like someone’s out to get you, they are. (Borderland, 7.22)
Rule #44: First things first, hide the women and children. (Rule Fifty-One, 7.24; first mentioned in Patriot Down, 7.23)
Rule #45: Clean up your messes. (Rule Fifty-One, 7.24)
Rule #51: Sometimes - You’re wrong. (Rule Fifty-One, 7.24)