For newest versions of the SparkFun thing, you can simply unsolder the “PWR” jumper at the back of the board. For older versions like the one I have, you can simply cut the trace between the PWR LED and the nearby resistor. After that, just power the project again. The reading on the multimeter immediately changed to 77 uA, or 0.077 mA. This means that the same project will now last on the same battery for … 3.7 years! Of course, this doesn’t take into account the characteristics of the battery, so in reality you will end up with 1-2 years battery life for your project.
I understand that sparkfun is some board that uses esp8266 for more comfortable use , but how this guys comes up with years ?