All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.
It is well established in the principles of Fiqh that in principle customs [or habits] and things are permissible and lawful and they cannot be changed from this principle except with authentic evidence [from the Book of Allaah and the Sunnah of the Prophet ] that is free from any objection which is equal to it or is more preponderant than it.
It is for this reason that our Imaams who wrote about ‘the Principles of Fiqh’ set a rule among the principles of the Islamic Fiqh by which the ruling is known on things about which no religious ruling is reported.
For instance, As-Suyooti said: “In principle all things are permissible unless there is evidence about their prohibition.”
There is much evidence about this rule in the Quran and in the Sunnah of the Prophet and you may refer to the evidence in the books of the Islamic legal maxims and, in general, the means are included in the customs.
Allaah Knows best.