Couple of issued to consider:
1. When a battery is brand new.. it really needs a deep charge "for several cycles" before you can insure its conditioned and all the cells are equalized... long periods of sitting on the shelf can allow weaker cells to drop... and when the charger quits putting in amperage and simply holds the voltage around 4230mv "battery protection prevents higher voltage" it takes time to get the weaker cells up to par with the stronger... once thats done, you can use it as normal.
2. Back to the first thought.... the meter will show full when its not really full.. some people pull it off the charger and go about expecting full battery capacity.
If you install "battery left" or monitor you mv readings with another app, expect its not fully charged "regardless of the indicator" until you reach about 4230ish "while on the charger" or about 4180 or so "immediately after taking off the charger.
A good rule of thumb is to just charge your battery when you sleep at night and normally it gets you through the day.. I you need a refresher because if heavy use.. fine, just do the longer charge once you go to sleep.
3. If she is in a marginal signal area the phone polls and eats up lots of battery trying to find a signal.
4. Also.. better not to mess locking onto a wifi signal, if the signal is marginal... all that does is cause the phone to hesitate and not switch to 3g because its trying to negotiate the wifi signal all the time.
5. The incredible has lots of social apps that run in the background ... not sure how much battery they eat.. but if your locked onto any, they can keep the phone from sleeping like it should.
I personally use "task manager" by rhythm software so I can pick and choose what I want to autokill verses ignore.
Things I personally autokill "works whenever the screen is off" are:
Mail "this is not gmail", Footprints, Peep, Friend stream, and photobucket".
I don't appreciate apps running without my permission.. if I want them, I'll pull their chain!
I still believe that people tend to use it much more then they think the first few days. New toy, setup and of course downloading apps. This all eats up the battery quickly. Keeping the screen set to a high brightness is probably number one though. The Incredibles screen is very bright and setting it to 35% still makes it bright, but does reduce the battery kill. Get Screebl and set it up. Then put your phone to 15 seconds before it dims. As mentioned, I have had it for two days, but am expected to get over 15 hours with my current use. Should only get better with time.