I carry at work with permission of my employer. In the state in which I work, permits are highly restricted. My permit is actually limited to work and my employer had to write a letter to the state police as a part of my permit application.
I would advise check your company guidelines or talk with a super. If nothing prohibits my opinion would be carry constantly.
When I first started carrying was back around 1984 in Los Angeles working at a 2-11,… I mean at a 7-11. After several threats to my life, I wanted nothing better than to be safe. The owner knew I carried and was okay with it. One day the store was shot up while I was behind the counter. Bullets went behind me and in front of me while one directed at me was stopped by the magazine rack. A shooting magazine stopped the bullet. About a week later the Corporation of Southland requested that I not work at the store anymore because I was apparently, “Putting other employees” in danger. The owner actually asked to buy my gun because he had to work my shift. So, I sold it to him. He got the 38 special but, I kept my .357 Magnum. So, there it was damn if you do, damn if you don’t!
I’m very fortunate that my employer is a 2A supporter. We are allowed and encouraged to carry. On a jobsite, whether or not we can/do depends on the owner and/or general contractor, as well as local, state and federal laws. In our shop most of us open carry.