zwyczajowy Anglais:

It's customary to tip the waiter

It is customary to send your apologies.

The man came into the library and sat down at his customary seat near the window.

Contrary to the wishes of the rapporteur, this customary law of Parliament's has been violated in this case.

This is her customary behavior.

She's not her customary cheerful self today.

Vanto had held the rank of ensign a full year longer than was customary.

In Japan it is not customary to tip for good service.

In particular, it is customary for actual examples of use of the harmonic mean to generally cover "average speed," and explain no further than that.

In Asian culture it's customary to take one's shoes off before entering a house or temple.