Well...for the most part in a desktop environment, you typically do not need more than 8gb of ram. People say to future proof your ram with 16gb....but I personally find that hard to justify because I may upgrade to Zen or Skylake in a year which utilizes ddr4 anyway. For gaming, emulation, and most everyday computing....8gb is enough. As for rendering...getting 16gb, as I understand it, will not speed up rendering in any noticeable way. If you're not exceeding the 8gb of ram you already have, then getting 16gb may be pointless. More ram do have their uses....but it's typically for server uses and purposes.
Bottom line, I find it hard to justify having 16gb based on my own uses....but hell, if you find a great deal out there...why not?
Bottom line, I find it hard to justify having 16gb based on my own uses....but hell, if you find a great deal out there...why not?