With the recent Apple confirming they slow down the phone (as they say) because of the battery, I checked and found my battery was in need of replacement. I wasn't about to take my phone to Apple to do the repair.
The repair with 90% well, the only issue that I has was removing the old stick adhesive strips, because of their age, I ended up breaking them into several pieces and having to pry the old battery out of the phone. Besides that the repair was very smooth. If it wasn't for those old strips I could have done the repair in 10 minutes or so (I am a computer technician so I am use to pulling electronics apart). Took only 25 minutes with that strip issue. The guide was great and easy to pause and follow.
I had no idea how slow my phone was until I replaced the battery. I definitely recommend this repair, now only it is a great value, but now I have the tools to be able to help my non-techie friends do this repair too.
The biggest piece of advise I have is make sure you have something to help pry up the battery if the OEM adhesive strips fall apart. But be careful with what ever you use because of the sensitive components in the phone.