“I believe the spec is that the battery is to maintain 80% capacity after 300 charges with a sharper drop off after that. I charge my smart phone every night, I expect I will need to replace my battery sometime this winter which I can do myself. If I had an iPhone, I would need to send it in for service.”
You might consider Applecare, which would cover a faulty batter for three years, at no additional charge (so to speak;).
With the iPhone 4, 80% of capacity would still be better than any comparable phone on the market. It will probably take me 3-4 years of use to exceed 300 charge cycles, but I only do it when necessary.
Even if you don’t recharge your phone, Li ion batteries don’t last more than a few years anyway. A new battery is about $30. I can change it out in seconds, I don’t need extended care for that.
As far as iPhone 4 battery life, I would not rely entirely on marketing specs.
I just double checked, I can get a replacement battery for my phone for $30, or for the same money, I can get a 2000 mAh (50% more juice) batter with a custom back cover to fit the slightly larger battery.
As it is, I generally have >50% battery life every night. I go ahead and give it a fresh charge because I don’t have to worry about wearing out the battery faster.