iPad was discharging quickly. Then it would not charge at all. Would not turn on or charge (dead). Determined the battery needed replaced.
Used the iFixit guide and was able to successfully repair. I used a hair dryer to soften the adhesive and was very patient (heat, cautiously pry, heat and pry, heat and pry). Once the glass was off the rest was fairly easy.
The pictures of the retaining clips could be more clear, took a while to figure out the clips. Maybe an exploded view of the clips 'locked' and 'unlocked' would have helped. Other than that the guide was pretty thorough and accurate.
iPad 3/4 Battery
iFixit Opening Picks (Set of 6)
iFixit Opening Tool