Marginal cost/value of employment

The less I spend, the longer I do not have to work. Where does the marginal cost of working go below the marginal value that can be obtained by acquiring extra goods?

A simplistic, but interesting way to look at this, is to assume that 1) we only work for the paycheck (no aspirational value in working), 2) we get paid a fixed wage per hour, and 3) we can work anywhere between 0 and 168 hours per week).

While its a continuous spectrum, we can think of this problem as one of tiers. Working 0-10 hours per week let's you survive, 10-20 hours per week provides food and shelter, 20-40 hours per week provides you with all the basic goods you need, 40-60 hours provides you the ability to support a family, 60-80 lets you live comfortably, 80-100 gives you financial independence until retirement, 100+ lets you consume anything you want.

If these were truly the decisions, would the work force look very different? How would people choose when to stop? Will marginal cost of work still vary across individuals? Will marginal value of work still vary across individuals?