I charge it in the evening, when I'm relaxing reading or watching TV. I can usually get it to 100% before I go to bed. If not, I'll put it on the first time I wake up to urinate that night.
By the time it gets to the next evening, it is usually at 55-65%.
If I forget to charge it in the evening (e.g, I fall asleep while reading or watching TV), it would probably make it fine to the next evening. In those cases, though, I'll stick it on the charger while I shower and have breakfast. That's more than enough to ensure no problem getting to the evening.