15/4/19 Cover all the bases
The idiom cover all the bases means (1) to prepare for every possibility, (2) to give attention to every aspect of a situation or problem, or (3) to inform (someone) of all matters at hand.
The origins of cover all the bases are not definitively established. It came about in the early to middle 20th century, and it is likely American in origin. Beyond that, there are two possibilities. First, the prevailing theory is that the idiom comes from baseball, where defensive positioning involves having players near all the bases. For the idiom to spring from this would be somewhat illogical as covering the bases in baseball is routine, while covering all bases in the metaphorical sense usually involves going beyond routine to be extra careful.
The second possibility is that the idiom has military origins. The phrase appears to have arisen during or soon after the second world war—that incubator of new words and expressions—and the word bases likely had strong military associations in people’s minds.