My experience is that if I send a check-in message once a day, that I never run down the battery, even after 3 months. I use lithium batteries, and then put in new ones at that point, using the old ones for another purpose. I periodically will also use the track progress feature, and don't notice any adverse impact on battery life, even using it for several days. 180 messages is a lot of messages to send for me using this device. The reason I put in fresh batteries every three months is so that, in an emergency, I am not adversely impacted by an almost depleted battery. I want to make sure the batteries don't age too much from infrequent use before I really need them to perform their primary function: keeping me safe.