how long does the battery last before replacing?
My harmony 900 Logitech is about 2 1/2 years old and at times it won't turn off the TV or turn it on and then if you wait awhile it does it.
They are rechargeable AAs. Not sure how much you can get out of the battery lifetime. But if you're asking how long between charges, I'm getting 3-4 days easily and wouldn't be surprised if you could get an entire week on a single charge depending upon your usage.