Heat Sensor

In a snake set up, where do people normally put the heat sensor?

Should you have one in each snake bin, or is it enough to have one sensor per thermostat controlling multiple heating pads? (assuming all the bins are set up identical)

As long as your have the same heating element providing one temp for all cages then you can use one thermostat as long as you do not exceed the wattage rating on the thermostat