i have an 04 wrx and the battery is killing out on me when i dont turn off the air conditioning and turn off the radio and turn off the automatic lights manuely. i have to usually sit in my car and rev it for a few seconds so that it has enough juice to start. i was thinking of just changing out the battery because it could just be bad. *note: it dosent die every time i dont charge it and follow the steps i just stated* any ideas?

Is it the original battery? If so it's probably shot, check the water level in the cells if you haven't done so already, you can also check the level of charge in each cell with a hydrometer. Most parts stores will test the battery for you, although of course they're interested in selling you a new one.
The OEM battery is marginal at best, and they aren't known for long life so you can't go wrong by replacing it in any case. Just be sure that the rest of the electrical system is ok so you don't ruin the new battery as well.

thanks