I use smooth preview for most everything but for the glasses, smooth preview creates a seam..but if I do a smooth on it, no seam. I keep my geo low poly except for when I want to do a final render, then I smooth everything and save it as a different file name. I try to delete history on everything, then after I do a smooth, I keep the history so I can control the divisions in the channel box.
Don't be satisfied with what you can do but rather strive to do the things you can't do!
Exceed Expectations!