I don't know whether I should upgrade my iMac to El Capitan or not. I'm planning to use it daily as my primary computer for the next 5 to 7 years (yes, seriously) and too afraid to update to the next OS because I think it will not be as fast as it is now. I value speed and efficiency much more than the cool new features. My question is: will updating my iMac to the new OS every year decrease its performance over time or not? iMac is used mostly for web browsing and Adobe apps (Photoshop, Illustrator, Premiere Pro, After Effects, Lightroom; in that order). I have very few files on my iMac because I keep everything in the cloud (~150 GB/1 TB) and there are ~25 programs installed. iMac (Retina 5K, 27-inch, Late 2014) OS X Yosemite 10.10.5 (latest) 4 GHz Intel Core i7 16 GB 1600 MHz DDR3 (will upgrade to 32 GB in the near future) AMD Radeon R9 M290X 2048 MB 1.12 TB Fusion Drive Thanks.