There are several ways of re-adjusting your zoom level. It shouldn't take more than a few seconds to reset the zoom to whatever amount you want, when going on a new map. There is the Magnifying glass zoom-tool on the left-hand toolbar where you can reset the Percent anywhere from 10% to 200% in a click. There is the zoom-slider at the top-right that you can drag to any zoom setting, one click. Or, third, you can just use your mouse to zoom (hold ALT or OPTION button, and scroll the mouse wheel in or out). Hope this helps you get to the zoom you want, more quickly!