Power is a huge consideration for many IoT devices. Will it need to operate on battery, scavenge power from other systems, or will it be plugged into the wall? If the device is running on a battery, how long does it need to last before being replaced or recharged? All of these constraints will play a role the MCU and sensors chosen to ensure low sleep mode power. Power constraints will also play a large factor in the wireless technology used. LTE is power hungry but high bandwidth, LoRa has great range and very low power but low bandwidth.
Test results showing that the product meets it's power consumption goals.