I had a cracked trackpad. On a tight budget I preferred to do the work myself. I was a bit intimidated when looking at the 20+ step process (Early 2011 Unibody, lots of steps :). But WITH THE RIGHT GUIDE AND TOOLS I was completely successful!!! I would suggest some hints to putting things back together, especially with the keyboard connection, which was a bit tricky.
GREAT INSTRUCTIONS accomplishing a complex task with EASE.
Time- 3 hrs (taking my time to make no mistakes)
Thanks to the tools and Tutorials from ifixit.com it went SMOOTH as BUTTER!!!! (but with out the mess :) I took my time looking at each picture with detail. The warning were great and made me double and tripple look at some things so I didn't break anything.
I did struggle a bit putting things back together, a couple times I had to restart :) With instructions to put things back together I may not have had to struggle putting things back together.
Pay close attention to the warnings they give. saved my Mac serval times.