Can you hear me cursor? Hello?
15 - 30 minuten
The trackpad on my trusty ol' mid-2009 MBP had started to act bizarro: It was occasionally non-responsive, and sometimes, it'd go totally mental and register multiple inputs (sometimes multi-touch inputs) simultaneously.
I'd originally thought that there might be some sort of software issue, as the Trackpad System Preferences pane had gone non-functional ("Could not load Trackpad Preference Pane"), and when I Airdropped a working file from another computer, it worked for a moment, but then it would crash System Preferences.
More time spent searching suggested that it was hardware related — spoiler alert: It was.
The repair was incredibly straightforward with the help of the step-by-step guide, and the tools from iFixit were perfect. Note: even if you don't think you need a Spudger, you do — I've been living without one and making due for a while, but holy crap, is it a great little tool.
There seemed to be a small amount of adhesive on my battery so getting it out of the case was by far the most difficult part of the procedure. I don't know if that's standard procedure these days (my battery was replaced at the Apple Store about a year ago — sidebar: if I had that to do over again, I'd DIY it... so easy).
I ordered a used trackpad with screws from iFixit, and though the trackpad is great, the screws were the wrong size. To be honest, I don't know why you'd need replacement screws unless you were to over-torque and break the ones that are already there. I'd recommend saving the dollars and reusing the ones that are currently in your machine.