I have some query pertaining to proper usage of cordless telephone batteries. Firstly, I want to know that for optimum usage of these batteries do I need to place the phone on the base phone all the time. Do I need to charge the phone all the time? Or do I need to recharge it only when battery life is completely gone? Also one other query about batteries do I need to get the same battery brand or I can replace them with battery from any brand. Are they battery specific? Please get back to me at the earliest. Thanks.