Let's suppose you have a 20-hour a week job that pays you $200/hour. What are the odds that job allows you to work an extra hour any time you feel like it? In

Let's suppose you have a 20-hour a week job that pays you $200/hour. What are the odds that job allows you to work an extra hour any time you feel like it? In the other direction, if you drop a few hours a week when you feel like it -- how long do you remain employed? Not too long, unless you're actually being underpaid for a specialist position. Let's suppose that you have a salary of $200K/year, and the boss generally expects you to be working on the company's problems 40 hours a week, with the occasional flex time when you or they need it. Do they pay you more on weeks when you work 42 hours? Less on weeks of 38 hours? No. (At lower salaries, overtime is real -- but a corporation is quite likely to fire you if you make a habit of taking or dropping hours without advance permission.) Almost nobody is in a position where they can directly and accurately value an arbitrary hour as income or loss of income.