Ok, I'm happy you seemed to have worked out a conditioning exercise for you battery life. I use my phone heavily every day, so I just pop it in the charger every night to alleviate any possible battery issues. I know my battery life would not make it 4 days, I've tested mine and get about 2 days(under my normal usage). Battery life has been discussed heavily in this forum over time, so there no shortage of views/opinions, that's for sure!
The below threads might be interesting reading to further dive into:
Battery Recalibration- Mobile Battery Discharger=Better battery life
How's your battery life so far? Let's discuss ways to prolong battery life...
Verizon 2100 mAh Extended Battery with new door