This is something that I have learned and practiced during the years I have been at a job.

The job gets hectic sometimes and very absent some other times.  You never would be getting work to do the proper 8 or 10 hours a day.  I have known many of my friends cuss about needing to work up to 14 or more hours a day and sometimes not have anything to work on.  It can be really jarring sometimes.

The key to it is to have a mental tally on how much you work for your employer and how much you work for yourselves. Some of the work you do for both.

What is the work you do for your employer? It is the work that runs the business and earns the revenue for the company or firm you work for.

What is the work you do for yourself?  It can be anything - from going out hiking, working out in the gym, reading books on lateral subjects - any thing that helps you improve the quality of your life.

There are some things that you can do for both.  For example - train for a particular skill. It helps you and it also helps your employer because they can use your skill as leverage.

Identify all the work you do and see if you can put them in these baskets.  Keep a tally of how much you do for your employer and how much you work for yourself.  Decide on a ratio, and see to it that the effort you put works in maintaining this ratio.  It may not be that you can do so everyday - but tend to maintain it over a week or so. If you overwork one day, try to do things for yourself the following day.

In effect, it will keep you satisfied that you are not being ripped off by your employer.  The 14 hour days will not feel like hell, and your quality of work and productivity would improve.  It is good for you and it is good for your employer.