Builds (commonly referred to as specs, or specializations) are identified by the names of the talent trees, with the tree with the most points first. A “Disc/Holy” Priest as 31 points in the Discipline tree, 20 in the Holy Tree. Usually, no more than 41 points are put in a single tree because that’s the required number for acquiring the highest talent. There are exceptions. The act of choosing a path is referred to as speccing. Changing a character’s spec is called respeccing, or is referred to as a respecc.
At level 10, players receive one talent point for each level they get. Players can spend these to enhance their World of Warcraft character, making it better than the default example of their class. Players will spend Talent Points to increase their enjoyment of playing their World of Warcraft character’s class, most especially by enhancing abilities that they find themselves using often, or to give new abilities that are useful to their style of play.
A spec defines the role a character will play in a group. A Protection-spec Warrior or Paladin makes for the ideal tank. The character’s spec can radically shift this role. A Holy or Discipline Priest will heal in an instance, while Shadow-specced Priests will DPS (Damage per Second) and control. Certain trees excel in PvE (Player vs Enemy) content, while some are useful for PvP (Player vs Player) content.
There is no best solution for anything in this game. World of Warcraft’s greatness relies on its many approaches to achieving any goal. Just as there is no best race for each class, there is never a best build for each class. Everything is a tradeoff – an increase in PvP efficiency means a decrease in PvE or endgame instances efficiency, and vice versa.
There are certain basic truths, such as “a mage is a DPS class”, “Hunters are good pullers”, etc., which are accepted while some talents are considered “bread and butter skills”. There are simple and natural ways to achieve things – if you want to play your Priest solo, it’s easier to spec him as Shadow Priest. By no means should this statement mean that “Disc/Holy Priests cannot play solo” – of course he can, it’s just more difficult.