Mixins vs Extend in Sass

Any opinions on using mixins vs. extends in Sass?

Here’s a few good articles:

Let me start by saying that I would generally advise never to use @extend at all. It is something of a Fool’s Gold: a feature with a lot of promise and twice as many caveats.

By now you likely know, mixins are the clear winner.
I have to say though, I’m surprised. I was an advocate of extends for the longest time, and went into this test thinking it would be a close race but felt extends would win purely on file size. Upon jumping into the test and watching gzip go to work I’ve been proven wrong.

@alexfedoseev, @samnang, Any opinions?

They could solve similarity of code reuse. Mixins support arguments, but properties declarations will duplicate for each place where they included. Extend will produce better css output(more concise), but they might affect from your output expectation when you use it for extend multiple selectors. I see Extend will work better if you use it with %placeholder instead of with css selectors directly.