What is the criterion for extravagance, and is leaving the room light on with the intention of returning soon considered extravagance, and is not turning off the satellite receiver after turning off the television considered extravagance?

Extravagance (israf) and wastefulness (tabdhir) are blameworthy in Islamic law. Israf is exceeding the limit in consuming permissible things, and tabdhir is spending something on what is not appropriate, which is a forbidden transgression. Therefore, lights that are not needed should be turned off. However, this should not lead to hardship, bearing in mind that some devices are damaged by frequent turning on and off, and some lights consume more energy when turned on again. In these cases, leaving them on is not considered extravagance.