Survival (Fallout 4)

Survival mode is a gameplay mode in Fallout 4 that introduces new aspects of survival into the gameplay.

Survival mode
Survival mode can be accessed in the options menu. Unlike Hardcore modes in previous Fallout games, Survival mode can be set before gameplay. Also, this mode can be toggled freely. Once Survival mode is activated, turning it off will prevent you from turning it back on for that save file.

Features in this mode are as follows:
 * Manual, quicksaving and almost all autosaves are disabled. Saving must be done by sleeping.
 * Fast travel is disabled.
 * The Sole Survivor deals, but also takes more damage.
 * Typically, threats are no longer displayed on the compass.
 * Locations of interest are harder to detect.
 * The Adrenaline perk is given.
 * Sole Survivor must stay hydrated, eat periodically, and have a regular sleep cycle.
 * Fatigue damage reduces Action points (AP).
 * Sleeping in a bed less than 7 hours does not heal Hit points (HP).
 * Illness and antibiotics are introduced.
 * The healing rate RadAway, stimpaks and other healing items is significantly reduced.
 * RadAway and chems can adversely affect the immune system.
 * Limbs no longer heal after combat and must be restored with a stimpak, sleeping in a bed until well rested, or by visiting a doctor.
 * Ammunition has weight and total carry weight is significantly reduced for both the Sole Survivor and their companions.
 * Companions will not get back up if downed in combat until healed. If left unattended, they will return home.
 * Robotic companions created in the Automatron DLC, excluding NPC robots like Ada and Jezebel, will now be destroyed if not repaired after being downed in combat.
 * Cleared locations take much longer to repopulate enemies and loot.
 * Enemies that usually spawn at higher levels will now spawn with regularity.

Gameplay differences


Wellness
There are five stages in each category of wellness that span in-game hours. It doesn't appear that the thresholds are linear. For example, it takes about 6 hours to go from well-fed to peckish to hungry, then 12 hours to go from hungry to famished. The following table shows the approximate times that it takes for a character to go from completely satisfied to the listed condition in each area. In-game time is expressed in "hours" and real-time is expressed in "minutes". These effects can be sped up when using certain items. Stimpacks and other drugs inducing dehydration, Rad-Away causing hunger, Etc.

''Note: The In-game / real-time data in this table are approximations only. The time expressed is not truly accurate. This table may be incomplete.

Tips

 * All illnesses can be cured by a doctor using the 15 cap "Cure Me" option in their dialogue. This is preferable over spending the caps on antibiotic supplies. It is therefore also recommended to have at least a level 1 clinic at your main settlement to use whenever you return.
 * Purified water is harder to obtain. Consider building two water purifiers at Sanctuary Hills as production for purified water is considerably longer and in lesser quantities. Save as many empty bottles as you can find. Fill the empty bottles with dirty water from lakes and streams to cook soups. Empty bottles can also be filled with purified water from manual water pumps, as well as Vault 111's and Vault 81's water fountains. It is also possible to drink directly from manual water pumps. Drinking from irradiated sources is not recommended, as each drink has the possibility of giving the player an illness.
 * For at least the first 10 levels, you may need to broaden your food options due to limited resources of food, at least until you build up enough crop and drinkable water for cooking. Consider hunting Radstags for immediate supply of food without risk of too much injury. Certain foods, such as soups and certain crops, satisfy both hunger and thirst. A good, renewable option is Noodle cups because you can now fill any empty bottles you find with dirty water and use them with a farm of Razorgrain.
 * Sleeping seven hours in a full bed ensures being well rested and minimizes risk of illness. For a quick save at a key location, sleep for at least 3 hours. If you only sleep for one hour in any bed, even at a workshop settlement, there is still a high risk for illness, in particular Parasites. Lethargy, Insomnia, and Weakness are also common with not sleeping well.
 * There is a high probability for contacting parasites during melee attacks on infected animals, in particular Radroaches and Mongrels.
 * Because a Fusion core now weighs 4 lbs, carrying too many cores may not be advantageous. You may want to consider elevating Intelligence to 9 as early in the game as possible, to access the Nuclear Physicist perk. This perk will help extend the life of your fusion cores. At the very least, as early as possible, fight your way up the skyrails of the Corvega assembly plant to get the Repair bobblehead in order to permanently increase the duration of your fusion cores by 10%, whether you're on a faction quest or not.
 * Because both you and your enemies are much weaker in terms of health, direct "guns blazin'" fighting will likely get you killed, especially in lower levels. The lowered health of your enemies does however make sneak builds incredibly advantageous, as it becomes much easier to kill an enemy in one hit, and it allows for you to fight one enemy at a time.