TEXT: 2a. Character Improvement
  Revolution D100 ver 1.0 – 15-Oct-2016. The following text is designated as Open Game Content.
  Improvement Sessions
  An Improvement Session marks the moment when the adventurers have terminated a scenario or an important section of it, 
  and can stop and meditate on what they have learned. In it, players can improve their characters' Skill and Characteristic 
  scores during Improvement Sessions. Improvement Sessions take place when the Time Scale enters Downtime and the 
  Narrator agrees that the situation allows the player characters to improve their abilities. A typical session will use up some 
  of the time the player characters have available, usually at least one week, but they should still be able to carry out other 
  typical Downtime activities (see the Downtime section in Chapter 3).
  Before explaining the exact procedure applied during an Improvement Session, we will first introduce the concept of Skill 
  Improvement Points and Skill check-marks.
  Improvement Points
  During an Improvement Session, each player receives an amount of Improvement Points to spend to improve Skills and 
  Characteristics. The suggested value is 10 for a full scenario, but may go as low as 4 for a small interlude or as high as the 
  Narrator wishes for the final chapter of a long lasting saga. You can use these points to increase your character’s Skills and 
  Characteristics, and to gain new Traits , as explained below.
  A player might not have the required Improvement Points to increase a Skill, according to the requirements set in the 
  “Improving your Character” section below, and thus need to save some Points for later use. He or she will thus allocate a 
  temporary amount of “saved” Improvement Points to the desired Skill and continue recording these unspent Points until 
  enough have been accumulated to buy an improvement. 
  Recording use of Skills
  You will mark a Skill as used when you have successfully employed it during a conflict to roll for effect, or to defend 
  against an enemy roll. You need not have won the conflict, it is enough to have succeeded in one opposed roll; one can learn
  from failures, too. Check-marking a Skill during an adventure yields one extra Improvement Points automatically allocated 
  to that Skill at the time of the next Improvement Session.
  You can theoretically mark a Skill used again during the course of play, but this should occur only if you used the Skill to 
  obtain a spectacular success, or when adventures span over very long periods of time and Improvement Sessions are rare. 
  The Narrator will decide whether a second success is worth a second mark or not. The maximum number of marks for the 
  same Skill is 3 in any case.
  Skill Slots
  Each Skill has a number of Slots available that depend on the Skill score. The number of Slots is equal to the Skill score 
  divided by ten, rounding up. This is based on the raw value for the Skill, not counting the +30% for Traits. For each Slot, the
  character can have one Trait or one improvement in a Characteristic. Once you have filled all Slots, you must improve the 
  Skill to the point that new Slots appear before learning new Traits or using it to improve Characteristics.
  Traits not taking up a Slot
  Some Traits are innate abilities, such as eyesight or hearing. Such Traits can be listed among “learned” Traits, but they do 
  not count for available Slot determination. In order to distinguish them from regular Traits, put a dot next to the Trait , 
  signifying that it does not take up any Slots. All humans have the ●Vision and ●Hearing traits, while trained hunters may 
  have the Acute Vision and Acute Hearing traits. Some creatures might even have ●Acute Vision.
  Knowledge and Communication Traits, even the most basic ones, are learned abilities and always occupy a Slot. Everyday 
  use of some abilities, like languages, do not require particular training. Therefore, the basic ability to speak or read any 
  
  number of languages occupies one Slot, no matter how many foreign languages you know. Exceptions may exist for some 
  imaginary languages involving non-auditory components. Acquiring new languages still requires the expenditure of 
  improvements to gain the new Trait.
  Other kinds of Traits may occupy the same Slot as other Traits instead of separate ones, but this is a detail depending on the 
  setting.
  Improving your Character
  During an Improvement Session, a player can spend Improvement Points to attempt to increase Skills percentages. The 
  number of Improvement points needed is equal to the current number of Slots for that skill, that is the current Skill score 
  divided by ten, rounding up. A check-mark from successful use of the Skill during play counts as one extra Improvement 
  Point spent towards improving the Skill, as do unspent Improvement Points allocated to the Skill during previous 
  improvement sessions. If check-marks and points previously allocated already match the required amount, the player need 
  not spend any more Improvement Points to improve that Skill.
  Experience check-marks not used at once to improve a Skill are added to the totals of unspent Improvement Points for the 
  relevant Skills. At the end of an Improvement Session, remove all Skill check-marks left on a character sheet.
  To improve a Skill, roll 1D100 and compare the result to the Skill to increase. If the roll is greater than the Skill’s current 
  score, the Skill increases by 2D4 points. If the result is equal to or less than the Skill’s current score, the Skill increases by 
  one point. A player can roll against a particular Skill as many times as he or she wishes during Downtime, provided he or 
  she pays the appropriate amount of Improvement Points.
  Learning New Traits
  In order to learn a new Trait, the character must either be able to research it (in that it is both researchable and the relevant 
  research material is at hand), or the Trait must be taught by a teacher (see below). Learning a new Trait costs one 
  Improvement Point and uses up one of the available Slots for that Skill; if no Slot is available, the player must first improve 
  the Skill to open up a new Slot.
  Background or Environment Traits can be neither researched nor taught. Only living for a long time in the related area can 
  allow a character to gain these Traits. As a prerequisite for Background traits, the character must first learn the Language 
  spoken by the culture as a Language Trait. Background Traits cost two Improvement Points to learn, while Environment 
  traits cost three.
  Studying with a teacher
  A teacher must have a score in the Skill taught that is at least twenty points higher than the student’s score in that Skill. In 
  order to have the opportunity to learn anything, a student must spend a number of weeks of Downtime equal to his or her 
  number of Slots in the Skill. The teacher must be present with the student for the entire period, and neither master nor 
  student may attend to other tasks during the training.
  At the end of the training period, both the teacher and the student(s) make an opposed roll on the raw score of the Skill 
  taught. The teacher can apply the Teach Trait to the roll, if possessed. If the teacher wins the opposed roll, the student obtain
  a Skill improvement of +1d4. Otherwise, the Skill increases by 1 point only. The student can also learn a Trait related to the 
  Skill and known to the teacher by forfeiting one point from the score gained, provided he or she has a Slot available in the 
  skill.
  If the teacher is teaching to more than one student at a time, each student makes an individual roll to oppose the mentor’s 
  one.
  Improving Characteristics
  Characteristics are improved in the same way as Traits are gained; by devoting one Improvement point to increasing the 
  Characteristic by one point. As for Traits, the Characteristic increase uses one Slot from one relevant Skill, that is a Skill 
  that uses the Characteristic to calculate its starting score. However, not all Slots can be devoted to Characteristic increase: 
  only one slot out of five can be used this way, and the other four Slots must already be occupied by Traits in order to be able
  to choose a Characteristic. The character need not have access to any research or teaching to increase a Characteristic. The 
  increase comes along with the gaining of fresh expertise in Skills that use the Characteristic.
  
  Example: Rotary the Barbarian has a Close Combat Skill of 44% and a DEX of 11. He has the Brawl, Shield and Spear 
  Traits. During Downtime, Rotary’s player learns the Sword Trait, so he now has five Slots available and four occupied by 
  Traits. He can use the fifth Slot for a Characteristic and chooses +1 DEX. His DEX is now 12, which does not allow him an
  increase in Might. In order to improve DEX again with Close Combat he needs to reach 91% with the raw Skill. Rotary 
  starts training his 32% in Agility instead, as reaching 41% in that Skill will grant one usable Slot, too.
  When a Characteristic is increased, recalculate the scores of all Skills and Derived Attributes based on it. If this opens up 
  new Slots in some Skills, you may use them immediately.
  Improving Motivations
  A player may choose to spend Improvement Rolls on a Motivation as if it was a Skill during an Improvement Session. As 
  for Skills, the number of Improvement Points to use is equal to one per 10% score or fraction in the Motivation. You will 
  find additional rules for Motivation improvement in the Motivation and Fate section of Chapter 3.
  Improvement Summary
  Action
  Improvement 
  Points Needed
  Notes
  Improve a Skill
  10% of Skill score,
  rounded up
  Improve a Motivation
  10% of Motivation
  score, rounded up
  Learn a new common 
  Trait or a Stunt
  1
  A Slot must be available in a related Skill
  Learn a new 
  Background Trait
  2
  A Slot must be available in a related Skill (usually Knowledge)
  Learn a new 
  Environment Trait
  3
  A Slot must be available in the Survival Skill
  Improve a 
  Characteristic by +1
  1
  A Slot must be available in a related Skill. Only every fifth Slot in Skill can 
  be used for a Characteristic gain.
  Dedicating to a Skill
  A character who needs to acquire more Traits than he or she has Skill Slots available can choose to dedicate to a specific 
  Skill. This choice costs nothing more than entering Downtime and deciding to do so, but eventually changing one's mind 
  may be costly, so you should not make it lightly.
  Once you have Dedicated to a Skill, your character has one Skill slot per 5% score or fraction in the Skill, not one slot per 
  10%. However, this means that he or she must devote half of his or her Improvement Points plus one to that Skill each time 
  he or she receives Improvement Points.  This makes Dedication to more than one Skill impossible.
  A player can move his or her character's Dedication from one Skill to another only if the first Skill has enough Slots for all 
  known Traits even with the standard "1 per 10%" computation method. The Narrator may let the character "unlearn" Traits 
  in order to gain enough Slots.
  
SOURCE: textdata/thevault/Revolution d100 SRD/RD100-SRD-02a - Character Improvement.pdf