2012 Macbook Pro OS?

[bodeh6]

So I have had my 13" Macbook Pro 2012. 2.5GHz. 500GB HDD, running Sierra I upgraded the RAM from 4 to 8GB earlier this year. I have been running Sierra since 2016/2017. I have had the machine since 2014. It works fine, but should I upgrade to High Sierra or Mojave?
Sierra doesn't get updates. I use Safari primarily for web browsing, but Chrome for Youtube. Safari is version 12.

 

[nothingtoseehere]

IMHO a supported OS is preferable, so I would recommend Mojave (runs fine at my 2015 machine). But many people do not mind to run older OS. As long as there is at least one officially supported browser, one can get along.
Some people say Mojave is a tad slower than Sierra on older devices which makes sense. If you plan to keep your MBP longer, how about an upgrade to an SSD?

 

[mikzn]

I have the mid 2012 MBP 15" very similar to your 13" (mine is i7 processor) and it runs fine on Catalina so you should be good for what ever OS you choose along the upgrade path

That said, I found it slow after the El Capitan upgrade and swapped out the HDD for an SSD - incredible speed difference and very easy to replace on these models for around $130 - $175

 

[justashooter]

I have this very MBP and it runs Mojave just great with an SSD. I have 16gb ram, but I use Photo editing programs a lot. I believe that Mojave is a better OS than High Sierra. You will be very pleased after installing an SSD.