There are quite a lot of studies that examine the difference between 'crunch mode' and 40hr type weeks. I've read that crunch beyond about 3 weeks results in less work being done per week than a 40hr week, and two months of crunch mode results in being behind where two months of 5day/40hr weeks would have got you. It also increases the risk of product failure.
Basically, if you believe that hitting a deadline is worth having overall less productivity for, you can reasonably crunch for 2 weeks, and have the third week as an acknowledged low productivity week, and it might be worth it. Anything much beyond that is counter-productive on pretty much all axes and a strong sign that management is incompetent.
Basically, if you believe that hitting a deadline is worth having overall less productivity for, you can reasonably crunch for 2 weeks, and have the third week as an acknowledged low productivity week, and it might be worth it. Anything much beyond that is counter-productive on pretty much all axes and a strong sign that management is incompetent.