I was at the field over the weekend and watched as one of our more experienced pilots hovered his 60 sized heli in front of the pits. Ever so slowly the heli leaned to the right and continued into the ground. Come to find out the switch failed in mid-flight. Had he been set up with two switches/batteries this would not have happened and would have saved him about $300

Oh well... if you've got the extra battery pack I say go for it... it's only a little added weight and can save your butt in a pinch.