I only -have- up to 40x dry, plus 100x oil. These days I essentially never use the 100x oil, though I'm glad it's available. In residency we had a couple of scopes with a 60x/"high dry," and I really liked them. Come to think of it, one I always had difficulty focusing with, but I always assumed it was dirty or scratched. Seemed like a good way to avoid oiling everything up when I didn't really have to; worked for me for everything except some heme and rare micro-organisms I wanted a better look at. Wish I still had a 2x, but that's a different topic.