Luck

Luck is one of the seven Primary Statistics in the SPECIAL character system. It represents Fate. Karma. An extremely high or low Luck will affect the character - somehow. Events and situations will be changed by how lucky (or unlucky) your character is.

Fallout, Fallout 2, Fallout Tactics
In Fallout, Luck primarily affects your chances with the virtual dice of the game, a high luck means you're more likely to succeed a roll, while the opposite is also true. Luck also affects the chance to score a critical hit on an enemy, with the standard being that your Critical Chance is equal to your luck (keep in mind, standard means without perks, traits, or aimed shots).

Fallout 3
Unlike other SPECIAL scores, luck has no specific skills associated with it. Instead, each point of Luck adds a half point (rounded up) to all skills. Having a high Luck will also improve your critical chance with all weapons.

Ways to increase Luck

 * The Bobblehead - Luck is in the cellar of Arlington House.
 * The Intense Training perk will allow you to increase your Luck (or any other S.P.E.C.I.A.L. stat) once for each time that you take it.
 * The Lucky 8 Ball also increases Luck by 1 as long as it is carried. The Lucky 8 Ball can only be obtained from Timebomb in Big Town, if you perform surgery on him (Medicine 40 required), and save the town after rescuing Red. After you help save the town, talk to Timebomb and he will reward you with the Lucky 8 Ball.
 * Lucky Shades can also be worn for another +1 Luck. These are located in Lucky's Southwest of Tenpenny Tower.
 * Lucky Shades cannot be worn with some helmets, particularly any Power Armor helmets, and likely any helmets with an existing transparent eye shield. They can be worn with the Raider Blastmaster Helmet, however.
 * Three Dog's Head Wrap gives +1 Luck and +1 Charisma. It can be acquired if you put a helmet in his pocket, return later when he is wearing it, then pickpocket the Head Wrap. Alternatively, you could just kill him for it.(But of course we don't condone such violence)
 * Ranger Battle Armor gives +1 Luck as well as +5 AP and +10 to Small Guns. The armour is a choice reward item for completing the Reilly's Rangers quest.
 * Naughty Nightwear gives +10 to Speech and +1 to Luck(Guess why). It can be found in Marigold Station.
 * Modified Utility Jumpsuit gives +5 to repair and +1 to Luck. It is a possible reward from the Trouble on the Homefront quest.
 * Tribal Power Armor and Ashur's Power Armor both give +1 to Luck, along with other stat bonuses. They are available from The Pitt downloadable content.
 * The Broken Steel DLC perk Almost Perfect raises all S.P.E.C.I.A.L. stats to 9 (be careful with Items that modify LUCK when taking this perk).

Luck also effects every random event in fallout examples are : THE alien crash(not the one with the radio signal) random deathclaw encounter with raiders and any other npc events

Luck-based Perks
Szczęście Удача