What does the expression «to put things on their shelves» mean?
If you have a friend who likes everything, even the smallest details, to be in order and for all information to be systematized, then they're a proponent of “разложить по полочкам” (“razlozhit po polochkam” or “putting things on their shelves”).
The expression originated in the early 20th century, but it didn't become widely used until the 1950s. It can be used literally, implying the bringing of order to something. For example, arranging objects according to a specific system. Or it can be used figuratively, which is more common when referring to a thorough explanation or arrangement of something.
In both cases, the expression is used to add greater emotional weight to a sentence.
An English equivalent would be: “Get your ducks in a row”.
