Always wear gloves at a crime scene. (Season 1, Episode 1, Mike Franks)

Rule #2

• Permalink: Always wear gloves at a crime scene.
• Rating: Unrated

Don't believe what you're told. Double check. (Season 1, Episode 1, Mike Franks)

Rule #3

• Permalink: Don't believe what you're told. Double check.
• Rating: Unrated

Never be unreachable. (Season 3, Episode 13, Gibbs)

Rule #3

• Permalink: Never be unreachable.
• Rating: Unrated

The best way to keep a secret? Keep it to yourself. Second best? Tell one other person, if you must. There is no third best. (Season 4, Episode 11)

Rule #4

• Permalink: The best way to keep a secret? Keep it to yourself. Second best? Tell one other person, if...
• Rating: Unrated

You don't waste good. (Season 8, Episode 22)

Rule #5

• Permalink: You don't waste good.
• Rating: Unrated

Never apologize. (Season 7, Episode 12, but referenced previous times without a number attached)

Rule #6

• Permalink: Never apologize.
• Rating: Unrated

Always be specific when you lie. (Season 1, Episode 23)

Rule #7

• Permalink: Always be specific when you lie.
• Rating: Unrated

Never take anything for granted. (Season 3, Episode 10)

Rule #8

• Permalink: Never take anything for granted.
• Rating: Unrated

Never assume. (Season 9, Episode 21)

Rule #8

• Permalink: Never assume.
• Rating: Unrated

Never go anywhere without a knife. (Season 1, Episode 13)

Rule #9

• Permalink: Never go anywhere without a knife.
• Rating: Unrated

Never get personally involved on a case. (Season 7, Episode 21)

Rule #10

• Permalink: Never get personally involved on a case.
• Rating: Unrated

When the job is done, walk away. (Season 6, Episode 24)

Rule #11

• Permalink: When the job is done, walk away.
• Rating: Unrated