Overtime (OT) is seen by most employers and employees as a fact of working life today, a virtual prerequisite for a raise in pay or status. From management’s point of view, overtime is assumed to be the most obvious way to achieve maximal output without hiring extra manpower.
You can get more work out of more hours for several days to a couple of months, depending upon how much longer the workday is. But there is a limit to everything and the limits to such overtime spurts are reached sooner than most employers and employees realize. And when those limits are reached, the spurts turn into bogs.

Studies show that cutting the workday from ten hours to eight hours, and the work-week from six days to five days, increased output and reduced production costs. Productivity starts to drop very quickly upon the transition to 60-hour weeks. At about two months of 60-hour weeks, the total work that people get done is about the same as what they would have got done in two months of 40-hour weeks. Beyond that, the costs utterly overwhelm the extra hours that are being put in.

It is not just productivity figures that go into counter-productive mode with overtime. More important at the personal level is the fact that Quality of Life (QOL), including emotional health, begins to go into a slow but definite nose-dive. Even if you are doing OT with a relatively low workload, there will be pronounced effects on your sleep patterns: problems of unwinding at bedtime, shorter sleep duration, daytime drowsiness. If you suffer sleep deprivation over a short term, you may be able to maintain accuracy on work tasks, but your speed will slow down.

Reducing sleep as little as one or two hours nightly can result in a severe decline in your mental functioning, sometimes without your being aware of the effects. There are other unpleasant effects of overtime on emotional health and QOL. Just a week of overtime, with a higher workload, has been linked to the release of increased amounts of cortical, the stress hormone.
Excessive overtime produced stress and stress-related ailments including high blood pressure, heart attacks and strokes.

One of the biggest productivity sinks created by excessive overtime is the increase in the number of errors you end up making. Sometime overtime situation arise. But out-of-control OT is the kind you are putting in either because you're not managing your workload efficiently. It is the quality of time put in, not the quantity. At the workplace, work comes first, not socializing or armchair gossiping. While a healthy stance on working hours means taking control of your life, which is bound to make you feel good, you should also be prepared and willing to accept some limitations on opportunities and accomplishments. You may have to forego an exciting new project, be unable to take on another new client. You have to be sure that this is the way you choose to live your life otherwise you are going to end up feeling conflicted.