Let’s look at some nice pictures from the ECE 3724 Chapter 8 PIC24 Startup to look at power on the PIC24.
Clock frequency and power usage are proportional. The less power used, the longer the batteries last.
The PIC24 can be reset in many ways.
The watchdog timer can be used to save power, by putting the processor asleep for short periods of time, or to prevent software malfunctions. The Pathfinder mission to Mars was rescued by a watchdog timer.