Unless you buy and aftermarket  extended battery that out weighs the phone, today's smart phone batteries are only intended to last 4-5 hours during moderate communication (much less under heavy call volumes).  There are so many features on these smart phones that you don't even have to talk to drain the battery, and I'm not going to deactivate them to save battery life because it is many of those other features (besides talking) that I bought the phone for (real-time updating weather, markets, news, etc.).  Therefore, one must purchase a third party's extended battery (for about $30-40+) in order to receive/maintain full value in your new smart phone (e.g. HTC Droid, etc.). 

I am finding that with many of today's consumer products that the retail price is only an entry price and that addtional monies must be paid in order to get the products to their 100% capability.  Seems like the term "ready" is being applied to a lot of products these days.  You additional money for the products to be ready, but even more to get what they are ready for.