Minecraft wiki entry for Redstone_tips, associated text: It can be helpful to choose a specific set of blocks the player uses to construct circuits. Then, when the player runs into these blocks during the excavation of new rooms in the base, the player knows they are about to damage a previously-built circuit. Common choices include stone bricks, snow block, wool and concrete. (Using different colors of wool and concrete is also a great way to keep track of different circuits)