I’ve had my Thunderbolt for two and a half years now. It’s a slow but venerable phone and has served me well. Unfortunately, over the past few months, the battery life completely died. I bought a new battery, which fixed that problem, but recently, it started shutting itself off at 80% battery life and after reboot claiming that the battery is at ~0%. After the next reboot, it would be back at 70-79% and A-OK for a little bit, except when it jumps from 70% to 15% and shuts off. So basically, it was time for a new phone.
With this battery-related craziness in mind, I decided to spring for a Droid Maxx. It’s much faster and, more importantly, has a huge amount of battery life. Paired with a USB recharger, I should have no problems when at a conference.