Working with an inaccurate transit or builder’s level can have serious consequences, especially if you're pouring concrete or building stairs. If you share a transit among several users, there’s no way to know for sure if it has been treated with care, so many builders will send their transit out periodically for cleaning and a checkup. This is a good idea, and generally less expensive than a layout mistake, but not something you’ll want to do very often. Between trips to the transit doctor, here’s how you can check the accuracy of your instrument: Find an area about 220 feet long and as level as possible. Place two matching leveling rods about 200 feet apart. Any two stationary
