Start with slope. Every mower publishes a maximum grade — commonly 35 to 45 percent for standard models, up to 70 or 80 percent for the AWD-class units built for hillsides. Walk your steepest section with a phone-level app and know the number before you shop. A mower rated to 45 percent on a 50 percent slope will slip, wear its drive wheels, and eventually refuse to climb.
Then obstacles. Trampolines, swingsets, garden beds, gravel paths, and low deck posts each need a rule in the app or a physical barrier the mower can see. Wire-free models handle this in software with no-go zones drawn on the map; boundary-wire models need a physical wire around each hazard, which adds install time. Count your obstacles before you assume either system is trivial.
Passages between sections matter too. Robot mowers need a minimum passage width — often 60 cm to 1 meter — to travel from one lawn zone to another. If your yard connects through a narrow side gate or a stepping-stone path, measure it. A mower that cannot self-navigate to the back yard is a mower you carry twice a week.
Finally, charging base placement. The base needs a flat spot with a power outlet, good drainage, and enough clearance to dock. Under a deck is fine if there is airflow; against a fence corner works if the mower can approach straight. If you have to run a long outdoor extension cord to make it work, the whole setup is fighting you.
MowerIndex · Updated Sep 2026