the battery lasts a lot longer on a charge. i hope this helps and let me know if you have any other questions! i really enjoy how light this serum is and that it has a nice slip to the formula, making it is easy to spread on the skin. 3. schedule a time to do this process every week, put an actual entry in your calendar. do you really want to make a difference, not only in your life, but in the lives of the people you're going to interact with? two experiments were performed under greenhouse and field conditions. 