A statue of Chen Wanting (1580-1660) – by most considered the founder of Chen Family style Tai Chi Chuan. There isn’t a clear dividing line between a style and a version of a style so we would describe the following as styles: Chen, Hu Lei (Thunder), Li, Shen, Spirit Dragon, Sun, Wan Sheng (also known as 10,000 Victories), Wu, Wu (Hao), Xiao, Yang and Zhaobao. With the possible exception of Zhaobao, and even there one sees a fair amount of cross-pollination, the styles have been influenced by Chen family style in varying amounts. Chen family style itself has several versions.
We believe the situation is similar to chess: there are plenty of openings for White and defenses for Black. In almost all cases one who would be a grandmaster has to have certain variations within an opening that he prefers either because of taste, the tournament situation or the opponent. In martial arts one needs to intensely study specific sets and techniques in order to master them, but it is usually worthwhile to have some familiarity with both versions of the chosen sets and with other arts.