Jedi Dress Code
The Jedi Dress Code was enacted by order of the Jedi Council in RR3323?. Some scholars believe that it was in jest, as the council enjoyed a relatively calm period and with few issues before it had little to do in session. However, what has evolved into the traditional Jedi Robes can be traced back to this edict.
As the council at that time had three members who were fur-covered, another two that whose physiology precluded this arrangement and another one that maintained ornamental naitive dress, this was obviously impractical at the time for even the council. Their subsequent act was to exempt themselves and as such the rule never went into force.
However, the traditional Human cultures, already maintaining many of these elements in their own dress code, informally adopted it and the jacket evolved into the robe as Core fashions changed. The boots have standardized in a Corellian/Corulag? spacer style despite their going in and out of fashion in the Core repeatedly.
For those not capable of wearing the standard uniform as well as many who do not take it as an order, the effect has been a muting of Jedi clothing and a removal of most of the local influences in a Jedi's dress.