So let's start from the beginning... I've had a 13' white MacBook for about 5 or so years. About 6 months ago the battery alert changed to "Replace Soon". My battery would usually die at around 50%, so while in use, I always kept it plugged in. My MacBook has been through some rough times. I almost always use it outdoors during the day (at WiFi spots), sometimes in very high heat... it's not had a gentle life. The screen suffered mild water damage about a year...