Ex bf took a construction job around the time he wanted to get clean. We did meth the night before he started. He went to work high, came home, came down, and didn't seem to want drugs much after that. We did meth 2 more times after that, a couple months later but really, for him the construction job took care of it. Working 10 hours, 6 days a week didn't leave much time or energy for drugs. And not much time to whine about withdrawal symptoms while running a welding torch either.
I love Dirty Jobs. Best show on TV, really.