If you use Screen Sharing to control or observe one Mac from a second Mac that has a smaller display, the first Mac’s desktop can look quite small (for example: Screen Sharing my 27-inch iMac from my 11-inch MacBook Air is an exercise in a lot of squinting). But Screen Sharing’s View > Turn Scaling Off/On option will let you get a 1:1 view of the target Mac no matter the size of your Screen Sharing window.

This makes it much easier to see what you’re doing and navigate the target Mac. Move your mouse near any border of the window to scroll around the target Mac’s display.