"Ins and outs" is an English idiom referring to all of the details surrounding some specific situation. A person who can claim to know this must have intricate knowledge of something to such an extent he or she can relate those details to others. This phrase implies a complete and utter comfort with some area of knowledge, allowing the person who has it to be an expert. While the origin of the phrase "ins and outs" is murky, it seems to be related to the similar idiom "inside out," which is often used in much the same way.
Idioms are short words or phrases that allow a speaker to converse with others on a level of familiarity that might not be available to them if the most literal words were used to convey the desired meaning. An idiom gains its intended meaning not from its origins or from its literal definition, but rather from the way it is used throughout time in a culture. One such idiom which refers to an impressive amount of knowledge on a subject is the phrase "ins and outs."
Any person who is said to have knowledge at the level implied by this idiomatic expression most likely knows every last detail about the situation in question. This phrase is often used to describe someone who has developed an area of expertise at a much higher level than the average person on some topic or subject. As an example, someone might say, "He can fix your television, because he understands the ins and outs of TV repair better than anyone I know."
This phrase is also used regularly in business settings. Many business projects have myriad details attached to them that only those people who are extremely knowledgeable would know. Those people that have such an intimate knowledge of a particular project are often the ones who are either spearheading it or working extensively on it. For example, consider the sentence, "I'd like you to give the speech to the shareholders about our new initiative since you know the ins and outs of it."
Like many idioms that have been around a long time, it is difficult to ascertain the origins of this expression. The meaning can be figured out from the phrase itself, since knowing something on the inside and outside means that it is known completely. Another version of "ins and outs" occurs when someone says that he or she knows something "inside and out."