Christianity insists on the concept of rest as a Christian ideal. You will meet pastors who will affirm they have not had a day off for 3 months.
The rapid turnover in the American pastorate is easily a symptom of the overworked pastor. Interestingly pastors grow in their work over a long careers so experience pastors tend to be far more capable of effectively running a church than young ones.
This raises a question if one can accomplish less by attempting to do to much. I think the answer in the bible is, yes.
The concept of Sabbath is that 1 out 7 days is devoted to rest. Sabbath is both practical wisdom and faith based.
The faith element is a trust that with good we can provide for ourselves with 6 days of labor even when 7 seem needed. The practical element is that when we become worn down our work begins to suffer, so working for 3 months without a day off most likely dramatically affects the quality of ones work.
Even Jesus rested and withdrew into the wilderness. If we need an example of rest we can find one in Jesus who rested even though the needs of the world around him were endless.