I just answered some of that on the FAQ thread...
That varies depending on several situations, but on average, you can expect about 4-5 hours of runtime for a warrior, 3.5 - 4.5 for a champion, and 3-4 for a hero.
Edit: To clarify, runtime means the saber powered ON. If you have it off, or only on periodically, it'll last days, even weeks.
To charge, depends on charger and charger type. So, like a warrior tier, where you remove the battery, the first charge takes a LONG time. Like, 12 hours. Best to put it on and leave it overnight. After that the charges get faster. I charge my warrior saber overnight still, but it's ready within a few hours. Champions/in hilt rechargers take a bit less time. 3-4 hours in my experience, also varying on how low/dead the battery is.
As to how long they last, that really depends on how well you maintain them and take care of them. Some batteries can last years, if properly maintained. Others, months if not. Just varies.