A:As for me , i used to change 2 times in a month with the average of 15-20 uses per day and after 2-3 months the batteries started draining faster even without using it much.
Q:Which model is better BP 11 or BP 12 of Morepen?
A:BP 11 is much more like a tried & tested version.Wheras BP 12 is just a small upgrade to it. Both will fulfill the basic role. It's not like mobile technology in which upgrades matters very much.