If you still haven't updated to High Sierra, DON'T. Sierra was a better OS, and there are no real benefits with High Sierra (unless you want to use an eGPU). It's basically the same system with a new slower file system (vs HFS), startup and overall response is slightly slower, there are various bugs depending upon which Mac model you use etc...etc... The latest 10.13.4 update made things worse, not better (introduced new bugs with both my iMac Pro and MacBook). This is like walking backwards into the future.