I work in an industry of some of the most advanced fuel cell and battery technologies out there. What Teksu stated here is correct. I would also like to add that each cycle (Charge and discharge) reduces the life of the lipo/lion. Keeping a lipo/lion at a fully charged state or fully discharged state is not good for long periods of time. Also, it does not hurt the battery to discharge it all the way till the phone cuts off. There is circuity that will not allow the cell to go below the voltage in which will cause harm to that cell. Same for overcharging.. Overcharging Lithium cells is very bad, so don't worry about that, it won't let you.
So charging everyday isnt necessarily a problem even if the batter has not been drained all the way?
