A completely different take on this phrase is that discretion means being discrete as in protecting people or information from exposure in some manner. If one is to be perceived as possessing valor by others, then they cannot express this by being merely brash and powerful.
Probiotics are essential (for at least a month or two after the antibiotics stop, depending on the potency) when you have had antibiotics to replenish the beneficial bacteria.
Perhaps the strongest evidence for probiotics is in treating diarrhea caused by a viral infection or from taking antibiotics. Both infection and antibiotics disrupt the natural balance of bacteria in your digestive system, which probiotics can help restore.