The 'enough' point

In economics, we learn about diminishing returns.  Imagine you have a plot of land a certain size.  When you first start planting, you'll find that each plant you plant will give you an increase in output.  As the plot gets more crowded, the increased output that you get with the addition of each new plant will decrease.  For example, at first, maybe you'll find that each tomato plant gives you 20 tomatoes.  When the plot gets crowded, a new plant may only get you 18, then 15, then 10.  And then there comes a point that it gets so crowded that the new plants will decrease the yield of the plants that were already there.

We also see the effect of diminishing returns for possessions.  If you have nothing, the first few possessions you get will bring you a great deal of joy.  Once you have your basic essentials, new possessions may still bring you joy, but not as much as those first few.  If you already have a lot of stuff, getting new things might actually start to be a pain.  You don't have space to store them.  You don't have time to use them or maintain them.  It becomes just another thing to clean and put away and think about.

This also works for activities.  It's nice to have a lot going on in your life.  But after a certain point, it can get to be too much and each new time commitment becomes more stress than enjoyment.

The 'enough' point is the point at which new possessions/activities bring you more harm than good.  This is the point where you've had enough.