Stresses of a trade? Never "plumbed" professionally, so I can't speak from experience. But from other non-software jobs I have had, I know it was easy to "leave work at work".
Software development followed me home, lived in my brain 24/7. It also caused a good deal of stress I was unaware of at the time.
I think the ease of leaving work at work is probably a better proxy for age and commitment to your job. If you know it is a short term job or career, it is easy to leave there.
If you need the job, you start to care. Even with manual labor, there are problems that didn't get solved that need to be worked out before 7 AM tomorrow. I would say it is even harder to leave it at work. If a pipe breaks, and water is pouring out, sleeping on it isnt an option
Software development followed me home, lived in my brain 24/7. It also caused a good deal of stress I was unaware of at the time.