What happens when satellites run out of fuel?

What's the ultimate fate of satellites when they exhaust their fuel supplies? Will they continue to orbit indefinitely, or will they eventually crash back to Earth? How do we prevent these defunct spacecraft from becoming hazardous space debris? And what measures are in place to ensure the SAFE disposal of these spent satellites? Given the increasing number of satellites launched into orbit, understanding the long-term implications of fuel depletion is crucial for sustainable space exploration.