From around the mid-17th century to the beginning of the 19th century, it was fashionable for
men in all walks of life to wear wigs. The shape of a wig was useful for setting apart different professional groups, and came to be associated with either
legal,
medical, or
military professions.
In the English judicial tradition, wigs are worn by the judiciary and the bar in the higher courts ( District and Supreme Courts), though they are not worn by magistrates and lawyers in the lower courts. It has been suggested in some quarters that the continued attachment to the use of wigs in the higher courts is pompous, irrational, and irrelevant within the modern legal profession, but calls to revoke the wigs have been met with strong resistance by the more conservative on the grounds that the traditions of the court, and the respect they invoke, must be upheld. That's exactly what I think when I see the numerous barristers of Sydney who have been evading paying taxes for years....
The bench wig, also referred to as a judicicial tye, evolved from a shorter wig called the peruke, which was popular in the early 1700s. The bench wig differs from a barrister's wig in that it only has one (vertical) curl, positioned just over the tail of the wig. Its size and shape make it more comfortable and practical (at least as much as it can get, I suppose) for court work than the full-bottomed wig. The bench wig is worn by District and Supreme Court judges of New South Wales while they are sitting on the bench.