[allachakb]

What is the criteria for deciding that one action of nabi was part of the culture & another is a sunnah.

[allachakb]

well, i considered all the actions done by rasulullah to be sunnah.
However, one argued that all are not sunnah. eg. topi and amamah are not sunnah since there is no mention of this in hadith.

[hasasnn2345tv]

Some consider anything that was commonplace during the time of Rasoolullah that he also did as not being sunnah, such as a topi or his clothing style. Others, like our ulama, disagree with this and do consider the topi and amamah as sunnah.

[casinobonuscxz]

You'll get a better answer about this questions if you ask to scholars on what is a sunna ta'budiya and what is a sunna a'diya.