1) if something wears you down, it makes you very tired, you lose energy and happiness. 2) it is the responsibility of the employers and managers to curb overwork. They have to do it. 3) it means "for example" or "in other words"

Thank you Miguel. Sometimes I feel a bit discouraged foe the high quantity of phrasal verbs. It's like each verb could becomes one of them

One of the meanings of "wear" is "To damage, diminish, erode, or consume by long or hard use, attrition, or exposure. Often used with away, down, or off." So the usage in this sentence is describing something physical (the erosion and breaking down of an object or tool) to describe something that happens to people's bodies, minds, or psyches: they get worn down too, just like objects. So it is is describing something physical and psychological, through the use of a phrase that evokes an image of physical degradation of things other than a body. It's a metaphor!