Here's a few good reasons why it's helpful to have a map with a printed UTM grid.
Plot a UTM coordinate onto your map
Determine UTM coordinates of any point on the map
Quickly estimate distance in kilometers between points
Provides north / south grid lines to more accurately measure a bearing from your map
Print free maps with UTM grid lines with the great mapping software Caltopo.
Here’s an example of a Caltopo map (MapBuilder Topo layer) with a UTM grid overlay:
Learn how to use the Cal topo from this YouTube video.