Is it better to replace my dying battery?

[Yakusoya]

Hi there. I have an early 2008 MBP (MacBookPro4,1) and have used it for a little over 4 years. The battery is starting to die on me whenever I use it portable so I've been using it as a desktop, plugging it in 100% of the time instead. The battery compartment looks normal, no bulges or anything.

I just noticed I am getting a "Service Battery" alert in the battery drop down menu. I didn't buy Apple Care so I don't think they'll be giving me a free replacement. Should I even buy a new battery since I only use it at home? And if I keep plugging in like this, will the battery explode?

I appreciate any help! Thanks!

 

[GGJstudios]

I just noticed I am getting a "Service Battery" alert in the battery drop down menu. I didn't buy Apple Care so I don't think they'll be giving me a free replacement. Should I even buy a new battery since I only use it at home? And if I keep plugging in like this, will the battery explode?

No, your battery won't explode.
Yes, it's bad for your battery to keep it plugged in all the time.
No, they won't give you a free replacement, unless your battery is defective.
Yes, you should buy a new battery.

This should answer most, if not all, of your battery questions:

Apple Notebook Battery FAQ​

 

[Big-TDI-Guy]

I doubt it's going to explode if you continue using it. I'm not keen on running without a battery installed. They make excellent little UPSs, even if they are in poor health.

Leaving it plugged in 24-7 will not accelerate its demise, contrary to popular legend.

 

[GGJstudios]

Leaving it plugged in 24-7 will not accelerate its demise, contrary to popular legend.

It's not legend. Apple clearly states otherwise.

 

[Big-TDI-Guy]

I would be willing to bet their logic in this is more for calibration / health monitoring of the battery.

Anything made with this chemistry needs charge and power management, which should automatically taper then dither the current once full charge is achieved. (to "condition" the battery).

Dealing with battery vendors, none ever advised mandatory cycling with Lithium polymer, with the exception of calibration of the charge monitors.