well, your computer either seems pretty good, or my computer is pretty average lol. You have twice more ram than me...
I personally would only upgrade my pc if it starts getting impossible to use it, like when my pc had 4gb of ram and opening unity could easily take literal hours. If your computer already have a hardware good enough for everything you need to do, then i don't think you should be upgrading all the time - too expensive, and it's also risky for you to break the other pieces of hardware from your computer