All the details; all there is to know

The new executive is very meticulous. He wants to know the pros and cons and the ins and outs of every issue

Il nuovo dirigente è molto meticoloso. Vuole sempre sapere tutti i minimi particolari e tutti i pro e i contro di ogni questione

Increased experience abroad has taught companies the ins and outs of foreign sales

Una maggiore esperienza all'estero ha insegnato alle società le regole del commercio estero

This expression suggests wholeness and entirety because of the conjunction of opposites. As far as the phrase's origin, some say "ins" originally referred to the party in government, and "outs" to the opposition