Specialization
Specialization refers to a player's decision to invest experience in only a few specific skills to make them powerful and reliable, rather than attempting to learn many different skills at once. Specializing is generally regarded as essential -- there is not enough experience in a normal game to advance more than a handful of skills to a high level. However, over-specialization can result in the character being unable to handle some of the challenges they face for lack of flexibility.
Benefits
Specialization in a particular skill improves the power and reliability of that skill's abilities. For example, specializing in Conjurations magic makes it easier to cast the offensive spells in that school (from Magic Dart on up), and they will increase in damage. By comparison, focusing on a weapon skill like Long Blades increases your accuracy and attack speed, while the Armour skill increases your AC gains and decreases spellcasting/evasion penalties from heavy armour.
Drawbacks
Over-specialization may result in difficulty dealing with certain challenges. It routinely affects spellcasters of all walks of life: for example, a Fire Elementalist who does not branch out into other schools of magic may have a hard time defeating monsters that are resistant or even immune to fire. Similarly, a melee character who completely eschews ranged combat skills will often be forced to rush through arrows and spells towards their opponents, or retreat for cover.
How to Specialize
Specializing is easy. Press the m key to access your Skills screen and see all the skills you currently know. These will be separated by spaces into four or five categories (Offensive, Ranged, Defensive, Magic, and Other). Pressing the key associated with a skill will toggle its training Off (dark grey), On (light gray), or Focus it (white) causing more experience to be allotted.
By default it will use Automatic Mode, which automatically adjusts experience division between skills based on use. You can also press / and swap to Manual Mode, for more control. In Manual Mode, experience is divided flatly between enabled skills, with Focus doubling a skill's percentage.
After adjusting the options to your liking, as you earn experience, your skills will automatically level according to your settings. Just remember that as you progress through the game, you will eventually gain entirely new skills. They will be toggled On by default if using Automatic Mode, or toggled Off if using Manual Mode.
Strategy
As you have full control over your skilling, it's best to specialize selectively. What does this mean for your character?
- For melee and ranged characters, it means focusing most, if not all, of your experience on one weapon at first. Unless you find an absolutely amazing weapon, once you specialize, you shouldn't switch weapon class. Afterwards, you can start investing in defensive and ranged skills.
- For casters, it means getting your main killing spells reliably castable (<= 10% failure) as soon as possible. Whenever it be Stone Arrow or Ensorcelled Hibernation, you will want to kill before you get close to being killed. Additional levels might be required to make the spell actually good at that task. Then, for as long as you're able, you should stick with those schools. Focusing on Conjurations in particular allows for a lot more flexibility.
- Some characters, especially those not worshipping a magic gifting god, might not find an lategame worthy spell of their school. Make sure that your currently useful spells are reliable, then dedicate everything else, somewhere else. Wait until after the Orcish Mines before doing this -- a book shop might just provide you wiht a spell. Alternatively, you can bide your time by investing in defense skills that will always be useful, swapping to melee if you don't find a great spell.
- Poison Magic is a big exception. The school might be good at the beginning, but does not scale well into the late game. Therefore, a caster may decide to invest a few, about 10 at most, points into the school to cast Olgreb's Toxic Radiance easily. Venom Mages and plain old Conjurers alike should get their killing schools up, then decide to switch into or out of Poison.
History
Prior to 0.9, experience was gathered and spent gradually as you performed actions related to each Skill. It was much harder to avoid unintentionally training certain things.
