An in-ground light sits level with the soil or the grass, so nothing stands above ground for the mower, the snow shovel or a foot to catch. At the base of a wall it washes the wall upward; in a lawn it lights a tree from a spot where a stake would be in the way.

Ours is 12 W, die-cast aluminum and IP67, and runs on the same 12 V cable as the rest of the yard. At 12 W it is the heaviest fixture on most runs, so count it at 12 W for the transformer, and see the wire guide if several share one run. It is an integrated LED, sealed because it lives in the ground; when it fails, the light itself is the replacement, on the terms on the warranty page.