Back when every boiler layout started with a pencil and paper
I learned to draft boiler plans by hand on huge rolls of paper when I first started. We used pencils and erasers, and every change meant redrawing whole sections. One time, a hand-sketched support bracket was off by an inch, and we had to cut and reweld on the spot. Now, with CAD software, we model everything in 3D and catch mistakes early. It's way faster and more precise, but I do miss the quiet focus of drawing by hand. My advice is to keep a tape measure handy even with digital plans, because real-world fits can surprise you. The tools evolve, but the need for careful work never goes away.