I have my personal rules for dungeon crawling campaigns that I developed over the years, but instead of just posting them. I decided to let people share their personal rules, maybe we can have an interesting set of rules this way.

I will start.

Rule 1: The rope is the best friend of an adventurer.

Rule 2: Always bring light sources with you. Even if everyone has darkvision. Like at least four torches, three sunrods and a lantern (preferably bull-eye).

Rule 3: Never trust an NPC, specially if he/she/it is accompanying the party.

Rule 4: If the DM laughs/grins/smiles after your rogue makes a Search check find an alternate route. I don't care how high he rolled.

Rule 5: All corridors are trapped, until proved otherwise.

See signature.

Rule 6: Just cause there were no traps on the way in doesnt mean there are no traps on the way out.

Rule 7: Always carry a dagger. Preferably three.

Rule 8: It pays many times to be a true coward, but only sometimes to be a true hero.

Rule 9: Never touch a chest or lever conveniently placed.

Rule 10: Never trust a healthy prisoner.

Rule 11: Try to choose your ground in a fight.

Rule 12: Slaves find traps faster and more efficiently than Rogues as long as they walk ahead of you by a healthy 200 ft. Bring lots of them.

~SE++

Rule 13: If the DM asks if you're sure, it's time to rethink your position.

~SE++

Rule 14: Bring knee pads.

(wait, wrong 'crawling'?)

~SE++

Rule 15: Never, ever, anger your DM.

Rule 15a: Unless it's really, really funny to do so.

Rule 15a.1: And you don't mind losing your character.

Rule 16: Every town has more adventurers, so use the ones you're traveling with as meat shields.

~SE++

Rule 17: Bards can get a party out of trouble just as often as they can get a party into trouble, but they are always fun to have around!

Rule 18: Never stick your limbs where you can't see them. That's what hirelings are for.