I've recently been given some Ryobi tools with rechargeable Lithium 18V batteries. As a result I now have 3 identical batteries, but only ever need 2. One of the batteries is still in the original package. In my experience these rechargeable batteries have a limited life and replacing them costs almost as much as buying a whole new tool. So.... from a long life point of view, would I be better off (1) puting all 3 into use right away, or (2) keeping one in the package until the others pack it in? Also, from a long life point of view, do you think a Lithium battery should be run right down (what I do now), or kept charged up?