My advice? Forget SASS, it's just taking something simple and making it more complex, harder to maintain, and to be frank if it DOES actually "save time" because you have enough CSS for it to actually do anything, there is something disastrously and horrifically wrong with your CSS... like using 200k of CSS to do 20k's job.
If you understand inheritance and how to use CSS properly, things like LESS, SASS and OOCSS are a bunch of garbage that serves no legitimate purpose other than "let's throw more code at it because we can!"
I really wonder what's in the kool-aid of people who use this type of stuff. Though to be fair I say the same thing about Bootstrap, jQuery, and all the other rubbish people are vomiting up broken slow loading websites with.