I use a mid-2012 at home too. The RAM/HDD slots have been updated multiple times. I love how long the device has lasted me.
When I bought my 2011MBP, I slowly upgraded the parts as prices came down.
My advice to people buying Mac laptops today is to max everything out if you can afford to, because you're generally going to be stuck with the RAM and storage for as long as you keep the computer. (Yes, I know you can upgrade the SSDs, but it's a little more complicated than running to your local computer store to buy commodity parts).
Right now, I'm holding onto my 2015 13" MBP with both hands (also maxed it on the same principle) until Apple releases a halfway decent MBP again. I use a 2016 15" for work, and still can't type well on the damned thing after having it for a year and a half.