I haven't done shading in my sketches for more than 25 years. Always felt like it could put the lines at risk of becoming unreadable. It is strange how we creatively change over time.
Pencil. Paper.
iPhone sketch done in Procreate pocket on my iPhone.
This sketch became a mammoth of a thing
Architecture doodle. Ballpoint pens on paper. Some UNI Jet-stream and Pentel.