The Discipline system is a method of combat customization options that are available to players after Advanced Class selection. Each Advanced Class has three unique disciplines, all of which have equivalents in the similar advanced class of the opposite faction (i.e., the Commando and Mercenary skill trees are essentially identical). The choice of the advanced class determines the three disciplines that are available.
The discipline system was introduced as a replacement to the previous Skill tree system, as BioWare developers wanted a new method to customization and unique player combat styles, claiming that the skill tree system was too easy to fill up with all of the abilities from one specific skill tree, leaving no room for other options. The new system gives players Utility points as they level up, allowing them to select several passive abilities from three separate tiers.
As with the skill tree system, respecialization is an option on the player's fleet or capital world, but all players who are not subscribers must pay a number of credits to respecialize.