Exactly like that water main mess. People forget that "saving time" upfront just means a way bigger delay later. Hitting something unmarked doesn't just stop work, it triggers insurance calls, maybe even permit reviews. That three day stop turns into a two week headache real fast.

Learned that the hard way when my spiral came out all wobbly. I started marking the bar with chalk before heating it up. The lines give you a guide to keep the twist even from end to end.