Abstract: An adjustable assembly with at least a pair of adjustable legs is used to stabilize a support element on a wide range of terrains. Each of the adjustable legs is engaged with a leg exchange bracket 13 that is adapted for and connected to a support element such as a sawhorse beam, a tabletop, or other leg-bearing support element. Each of the adjustable legs can be variably adjusted to adapt to height and other terrain surface variations so as to provide an essentially steady and generally level support surface. Once the desired adjustment is selected, the legs are locked. If the terrain changes or there is a need to transfer the support surface to another terrain, the legs can be readily unlocked, the position of one or more legs adjusted, and the lock(s) re-engaged to provide a steady and generally level assembly on the changed terrain.