I know this question gets asked every so often, but I haven't seen it in a while. I'm curious about what tools and processes everyone is using to cover all the different versions their products and websites will see once they're live.

Are you using the Anima Auto-Layout or default Sketch tools? Do you have defined grid systems for specific breakpoints? Are you creating mobile layouts first? Are you defining breakpoints in the browser or in design software? Are those breakpoints defined by the content or common device sizes? etc.