FWIW my late 2013, 15" MacBook Pro seems to me just as good as new. Never had to replace the battery or have any kind of service done on it at all.

I kind of want to buy a new model but this thing just keeps going so I have no legitimate reason to do so. Honestly, I really love the machine. The fact that I'll get at least eight years out of it, as I did from my last MBP, means I'll definitely buy another MacBook Pro.