Bad battery! Any residual effects? Why and how does this happen?

Hello,

I have been having battery issues with my Mac for the better half of a year. Cannot hold charge, will not hold charge, and completely powers off when not connected to power source. From what I can tell, there doesn’t seem to be a considerable amount of swelling, but I am sure there is still some present. I’ve read about this problem countless times. Looks like it’s finally time to get a new battery, I’ve had enough. Tried countless times to reset the SMC and PRAM with no effect. Bought a new charger, which I needed anyway, with also no effect. Thus, I am hoping that replacing the battery will rectify the problem. I plan on purchasing the battery replacement kit from this website once I have enough funds. Any college student discounts?

My question is, based off of your speculation/experience, have I done any harm to her by neglecting to get a new battery?

As a young engineer, I am curious as to how and why this happens, assuming that it is in fact the battery. Battery memory effect?

Check out this screenshot below.