Depends on what you need your MBP for and if you took care of it (casing, keyboard, screen, etc). I upgraded my MBP 2009 and MBP 2012 with RAM, SSD's and even a new battery for the '09 and both still work excellent. My wife uses the '09 for watching YT, browsing and email. I use the '12 for the same plus office work plus some pictures and movie editing. Is it a speed monster? Depends on your standards (and patience), but with the upgrades it still gets the work done well. I will keep them till one of them fails and then it is time for a new one.
Good luck with the decision.