I upgraded everything in my Snow Leopard-era 13" MBP and it was still running fine until I stupidly spilled water on it last month.

Now replaced by a 2015 13" MBP, which feels almost identical (although that Retina screen is goooood... as is the HDMI port).

And I can still sell most of the 2011 MBP parts on eBay to get some of my investment back!