Every robot mower answers one question: how does it know where your lawn ends? Boundary-wire mowers use a perimeter wire you bury or pin around the lawn once. Wire-free mowers use GPS-RTK satellites, cameras, or LiDAR to map the yard from an app instead.
Boundary wire is the proven choice. It works under dense trees, beside tall walls, and in oddly shaped yards, because the signal comes from the wire, not the sky. The cost is the install: plan a full weekend, or a few hundred dollars for a professional. And when a wire breaks — aeration and edging are the usual culprits — you will be hunting for it.
Wire-free is where the category is going. Setup drops from a weekend to an afternoon, and re-mapping after landscaping takes minutes instead of re-burying wire. The trade-off is signal: GPS-RTK models need reasonable sky view, so heavy tree canopy pushes you toward LiDAR or camera-based models instead.
The short version: shaded, complex, or wire-tolerant yard — boundary wire. Open suburban lawn, or you would rather not dig — wire-free, with vision or LiDAR navigation if you have tree cover.
MowerIndex · Updated Aug 2026