Sure beats paying out the wazoo at the Apple Store.
15 - 30 minutos
Spilled orange juice on my Macbook Pro a while ago, and recently the mouse had started acting crazy and erratic, jumping around and not going where I wanted it to.
Replaced the trackpad and battery, since it seemed like trackpad issues were often battery expansion issues. Took about 15 minutes. The online guide was really helpful, especially the color-coded guide to screw size and placement.
I bought my new battery from Amazon, and it came with a tip for SMC reset: shut down the computer, plug in the power cord, and press shift-control-option (left side) and the power button at the same time. Then let go of all four and turn on the computer!
Tri-point Y1 Screwdriver
MacBook Pro 13" Unibody (Mid 2009-Mid 2012) Trackpad