I work at a popular coffee shop and the only time I'll ever smoke before work is if I'm working evening shifts. Morning shifts are way too busy and it would kill my buzz/high. When I work morning shifts, I get a 10 min break 2 hours into my shift and two hours before the end, and I usually smoke a bowl during my 2nd 10 minute break, depending on who I'm working with that afternoon.

Some of my co-workers smoke as well, and some (mostly the supervisors) don't.