Indeed, that's why apps like iStat Menus, Stats, Sensei etc (for macOS at least) are very useful, I keep the CPU usage and power usage in my menu bar at all tim

Indeed, that's why apps like iStat Menus, Stats, Sensei etc (for macOS at least) are very useful, I keep the CPU usage and power usage in my menu bar at all times, this is very useful on battery. For example I know that my Macbook Air idles at ~2W-5W, so if I'm doing nothing special and it's using 15W, a process is doing some funny stuff