What can damage my blackberry power management ic?

My blackberry 9000 was working perfectly without any problems but the battery drained and it suddenly switched off, i looked for the charger, (weak charger) and i kept the phone on it till it started again, there was a message and i wanted to read it, so i started chatting again, and the phone turned off again, i left it to charge so it started but this time when it started i just put it on stand by mode and went to sleep, in the morning it wasn't working at all, and when i do a battery pull and place it back, the red LED comes on for 10 seconds then nothing else happens, i took it to a shop and they told me that the Power Management IC has to be replaced, it cost me US $40 and my friends told me it will happen a lot, so how to avoid this happening again ? It also fell 3-4 times the same day, and i used it once with my wet hand. So which one of these the reason for damaging the Power IC, or is there other reasons ?

Thanks In Advance !