I had a digital copy scanned of the plans for my project. I work from the screen for planning, but print portions of the plans for the things I'm working on. If they get messed up, I can always print another one. If I'm going to cut out a metal part, I print it out on sticky back labels and stick it to the metal sheet I'm going to cut it out from. I rarely look at the original plans.

As mentioned above, use caution on the scaling.