My first lead tech in Dallas swore I'd never learn to fish walls in old homes, and he was dead wrong
He had 22 years in and said the plaster and lath in those 1940s houses would eat me alive, so I practiced on my own place for a month before my next job. Anyone else have a mentor call it wrong like that, or was he right about your market?
Sounds like your old lead tech was protecting his own job more than teaching you anything. Plaster and lath is stubborn but its not magic, you just gotta go slow and keep your holes small so the keyhole saw doesnt wander. My own mentor told me I'd never get a fish tape past a fireblock without tearing out drywall, then I watched a guy do it in ten minutes with a chain and a magnet. Some of these old timers just repeat whatever scared them back in 1995 and call it wisdom. Practicing on your own place first was the smart move, thats how you actually learn instead of standing around getting yelled at.