This screen is a simple one to configure a few settings in regard to the Estimates feature.
It is accessible through the Admin --> System Configuration --> Global Estimates Settings
Enabled - This is a global switch to turn on/off the Estimates feature. This must be turned on before any estimate sales order records are created and/or any estimate events are created.
Consumption Day Range - This is the range of days in which the estimates will look for an actual sales order that matches the estimate, and then causes the estimate to consume itself down. For more discussion on estimate consumption, see the Estimates topic.