I read a tip that you should use a flashing around the tub edge if you are installing a new tub. Has anyone ever done this or is this just extra fluff that isn't really needed.

It all depends on what you're using as a enclosure. On cement backerboard they make a plastic insert that prevents moisture from seeping past the wall while tile men tile and grout right down to the tub. Perhaps one of the other experts can add more. We don't do any of this. Our job's done when we set the tub and connect the water and drainage. Good luck, Tom