Bought a Macbook Pro second hand and after one year the battery died causing my mac to slow down to to a crawl. I thought for a moment about throwing it out the window but then thought better of it.
the repair was quick and easy I had the battery and tools...and the how to guide. It was done in a snap.
don't throw it out the window.
Tri-point Y1 Screwdriver
MacBook Pro 15" Unibody (Early 2011 through Mid 2012) Replacement Battery