It depends on which unit you are in. Generally, the on-site budgeter is at the scene, and the cost engineer of the consulting unit will occasionally travel to check the quantity. Time depends on the size of the project. In fact, business trip is quite good, free travel and high subsidies! Most importantly, the chances of promotion are greater than others.
If you are bidding and planning business in the company office, you don't need to go under the project. Sometimes it's just a business trip. It won't take long. It depends on how specific you are when you allocate it. Everyone in the office has connections. I hope I can help you.