The math piqued my interest, so...
Assumptions:
a) 9 hours for a full charge (from an earlier poster)
b) a 5% capacity loss for every 100 full charges (I got this from looking at a graph at BatteryUniversity)
c) 6 hours read per day
d) I only care about the small battery
This is what I came up with:
After the first year, Capacity is down to 7.8 hours (and went through 260 cycles)
After the second year, Capacity is down to 6.5 hours (and went through 563 cycles)
After the third year, capacity is down to 4.7 hours (and went through 960 cycles)
I may be completely off about this.
