Most things I do on a daily basis have become digital - I spend far more time touching a keyboard than a pen. On the whole, I'm fine with this change. I find PDF annotation to work well when reviewing manuscripts or grants and track changes is great for collaborative writing.
But the one time I just can't manage to avoid killing some trees is in the final stages of writing something. For me, I need to print the document out and see it in the broad sense - spread out the pages and make sure sections and ideas are where they should be. I can't confine that part of the process to a screen, even a large one.
I wonder if that will make me old fashioned in the years to come.