Been pushing my device all day with it's 1800 mah slim battery (phone calls, messages etc) and while sitting in class the battery meter dropped to 30% and then 20% on my way home. I put it on the car charger but it didn't do much since it's only a 10 minute trip home.

I get home only to discover the power is out due to an electrical storm in the area and my home phone is out. I was lucky enough to have a spare Seido 1650 laying around so I popped it, powered up the phone and the meter showed a full charge.

Thankfully they built these devices with replaceable batteries- can you imagine having a low or dead battery and needing to make a phone call in an emergency?