Guides:XP
This guide is a discussion of the relative merits of different methods for human characters to gain XP and level up, particularly in the early stages of character development. Please see the Experience Points page for a complete list of methods of earning XP. Since zombies can only gain XP through combat, they are not discussed here - see the zombie guide for discussion of the best skill choices.
Combat
Privates, firefighters and police officers all start with a weapon and a combat skill which gives them respectable hit rates and thus they are best off using combat to gain XP.
Firefighters start with Axe Proficiency and a fire axe. This gives them an average rate of XP gain of 0.75 per attack, meaning they can gain 30 XP a day with 10 AP left over for finding targets and returning to their safehouses, with no AP ever being required for searching and reloading. After taking the Hand to Hand Combat skill this rises to 1.2 per attack, allowing leveling up every two days or so. It is not surprising that many players consider the firefighter the best human class in the game. One popular strategy is to start by patrolling a small area attacking all the zombies present to find out how many Hit Points (HP) they have, and then killing the one with the lowest total to earn the 10 XP kill bonus.
Privates and cops start with Basic Firearms Training, which gives them a 30% chance to hit with all ranged weapons, a pistol and (for Privates) 2 spare clips. Additional guns and ammunition can be found in gun stores, police departments or, in the case of shotguns, pubs. Ranged weapons deliver high amounts of damage per attack (average 1.5 for the pistol starting out, and 3 for the shotgun), but the necessity to search for new ammunition and reload the weapons means that the average AP spent is higher than for the firefighter. However, it is much easier for a ranged weapon user to kill a target completely in one session and thus earn the extra kill bonus. Any character primarily using firearms should consider training in Free Running early on, because Police Departments (the most common source of ammunition for pistols and shotguns) are often so heavily barricaded that you can only enter using Free Running.
Untrained characters determined to gain XP from combat are best off with the fire axe (though they will have to search fire stations for a short while to find one) with its average damage of 0.3 HP per attack with no searching/reloading necessary. Knives are also a good choice, with less damage but higher accuracy, which comes to an average damage of 0.4 per attack. However, the other methods of XP gain available are probably better.
Players using combat to level up are best off choosing their early skills from the tree relevant to their preferred weapon. Since attacking one's own side earns only half the XP, PKing is not a good route to leveling up.
DNA extraction
Characters with the NecroTech Employment skill (the starting skill for Lab Assistants) can get 4 XP a time for using their DNA Extractor on a zombie, unless another character has extracted that zombie's DNA in the same 24 hour period. This can be a very quick route to gaining XP. Taking this skill early on is a good idea for characters looking to pursue a support role and keen to level up quickly -- the necessary DNA Extractor can be found relative quickly by searching NecroTech buildings, and only one is required.
However, as the game matures, more and more high-level zombies (or those that do NOT wish to be revived) are getting brain-rot, therefore DNA extraction is getting harder. It also requires you to get close to zombie hordes AND spend time near them, during which they can attack you. It may work better as a secondary source of XP.
To maximize the yield, you need to save up as many APs as possible, have at least one first-aid kit ready (for yourself in case you got infected), and free-running (it really helps), and good intelligence on where zeds can be found. Then get as close as you can and then pop out to sample as many as you can. If you run into more than one "cortex damaged" move on to the next group; try to figure out the most efficient route. Remember to save 10-20 AP for your retreat!
First Aid
The best method of gaining XP open to characters starting in any other class, including the non-Private military classes, is to heal their fellow survivors. This involves searching hospitals for first aid kits and then seeking survivors in need of healing. (Consumers are better off using their Shopping skill to search the drugstores in malls, which gives a significantly higher chance of search success.) The best way to find injured survivors is to look for people caught out on the streets, who have probably been attacked by zombies, or to wait in safehouses for people to request healing. Attempting to heal someone who is already at full health will waste an AP but not use up the first aid kit.
Ironically, Medics are at a slight disadvantage when using first aid to gain XP, as their possession of the First Aid skill means they need fewer first aid kits to heal a certain amount of damage. They also gain less XP. For example, say a patient is at 35 HP. Without First Aid skill you would need 3 kits to fully heal the patient, resulting in 15 XP. If you do have the skill, you only need 2 kits, resulting in 10 XP. While you do have 1 kit left to be used on someone else, that would take more time.
With the advent of the Infectious Bite ability of zombies, first-aid becomes even more critical, as it's the only way to stop the wound from festering. Many zombies seem to be biting each survivor once (rather than trying to kill just one survivor) when they are able to breach a building, meaning many people will need curing. While almost anyone can locate and carry first-aid kits, most players tend to leave that to the healers/medics and call for them when they reach a safehouse.
The best skill for those keen to use this method of leveling up to take early on is Diagnosis, since it prevents the wastage of APs on healing characters who don't need it. This makes the Doctor one of the better starting classes since the change of first-aid to diagnose. Note, though, that some players consider low-level characters possessing Diagnosis and a combat skill to be likely PKers, using their Diagnosis ability to look for easy targets. Also, by spending 1 AP in a safehouse to ask if any one needs healing, you can know who WANTS to be healed.
The main problem here is locating first-aid kits. While hospitals are logical choices they are also zombie magnets. A suggested tactic would be to save up a large amount of APs (at least 35), pick the hospital, run inside, search for first-aid kits until you are down to 9AP, and then leg it back to your safehouse.
Many new players who lack offensive skills must resort to healing others to earn EXP. However because of their low level they still lack Diagnosis and don't know who to heal in a large safehouse. Asking doesn't always work because the next person to log in will heal them first. An alternative to healing your fellow survivors is to heal the Zombies. Because you simply use it on A Zombie rather then a specific survivor, you'll be instantly checking all the zombies in the group for healing and can quickly gain EXP. The catch is of course that you're now healing the very creatures trying to kill you. To avoid helping those you don't want to help you can try and find a Revivification Point and use your first aid kits there. This ensures that you heal people who want to be alive again and even helps them out a little if a newbie comes along and attacks them not knowing any better. Please remember that this method is meant only for Level 1 characters without any offensive skills and can't locate anyone who needs healing.
Other methods
Most other XP-earning activities are more useful for their effects (revivification, preventing bodies rising again within the building, delivering messages via graffiti) than the XP they give. The rate of XP gain from reading is so low that it is really only of use to characters being roleplayed as panicked survivors absolutely determined to minimize their exposure to danger.
Sustainable Zombie Harvesting
It can happen that zombies become hard to find. To maximize your XP gain when you do find a zombie, use medkits to heal the zombie. You get 5 XP for the healing plus the opportunity to gain 10 more XP by damaging the zombie. You can do this multiple times, i.e. if you use 4 medkits this way it could be good for an additional 60 XP. If you are public spirited you can leave the zombie near full health for other survivors to practice on, although you maximize your XP gain by finishing the zombie off before going back to your safehouse. However, doing the above is likely to earn you the label of zombie spy, meaning other humans will kill you.
If you're really mean, you can look for some zeds hiding in an "wide-open" building, close the door or barricade it slightly, then dump any bodies outside. Some newbies may just stand there and let you do it until they figure out how to get out. (You get out by clicking on any nearby building.)
