My original battery in my 2007 CX7 appeared to be going bad a little after 3 years so I replaced it but that wasn't the problem. If I don't run the car daily I need to jump start it. I made sure that the battery connections are clean and tight.
Test the charging voltage that should be ~ 14.4 volts at a fast idle. In addition, make sure all interior lights are off including a radar detector or other extras.