I usually charge them up the night before. As I'm a newbie (not a newbie newbie anymore), I asked around about how long I can let them go. If I don't make it out the planned day I feel safe up to about three days or so wothout recharging again. If I get nervous I just chuck them on the charger at lunch time at work. Lots of open space around a plug-in is a great thing to have. Haven't had a problem or a wiggle or anything .