If your lives are full, why can't you get free lives from others?

You get five lives on top and ten on the bottom. We like to request lives as soon as possible. You have to have used all lives on top (which replenish one life every 1/2 hour) and one on the bottom before you can request lives. You can only make that request every four hours. There are two ways to move them up top to use. One is in a lump sum of five. The other is one at a time. I use one at a time. You can earn up to five lives as an award in the star chest on the left. It only happens every so many levels though.