How long does a robot mower last?
Updated August 2026
The mower itself lasts 8–10 years, but the battery inside it gives out first, usually at 3–5 years. The small razor blades wear even faster, needing a fresh set every 6–10 weeks in the cutting season. So the honest cost of a robot mower is the machine plus one or two $100–300 battery packs and a steady trickle of cheap blades across its life. Whether the chassis reaches 8 years or 10 comes down mostly to how you treat that battery: keep it out of the sun on the dock, and bring it indoors over a cold winter.
Lifespan by type and situation
| Type or situation | Typical lifespan | Why |
|---|---|---|
| Whole unit (body, motors, deck) | 8–10 years | The chassis and drive motors set the ceiling |
| Lithium-ion battery | 3–5 years | Expect one or two replacements over the mower's life |
| Cutting blades | 6–10 weeks | Cheap razor blades; a worn set tears grass and drains the battery |
| Buried boundary wire | 8–10+ years | Lasts as long as the mower unless a spade cuts it |
| Wire-free / GPS-RTK models | 8–10 years | No perimeter wire to fail, but pricier to replace whole |
| Stored indoors each winter | Top of the range | Cold and damp age the battery fastest |
Signs yours is near the end
- Runtime per charge dropping well below what it managed when new, a fading battery
- The mower cutting shorter sessions or failing to finish the lawn on one charge
- A ragged, torn cut and clumps left behind even with a fresh set of blades
- Wheels or drive motors that slip, stall, or leave it stuck on gentle slopes
- Lift, tilt, or bump sensor errors that persist after cleaning the underside
- The battery taking far longer to charge, or refusing to reach a full charge
How to add years
The battery decides everything, so treat it well: bring the mower and its dock inside for winter in cold climates, keep it out of direct sun on the charging base, and let it charge fully rather than topping off constantly. A replacement pack runs $100–300 and buys another 3–5 years, which is why a $1,500 robot is usually worth re-batterying once instead of scrapping. Swap the razor blades every 6–10 weeks (a set is $10–25) so the motors are not straining against dull edges, and rinse grass off the deck monthly. Compared with a gas walk-behind mower, a robot trades engine upkeep for battery replacement; either way, a simple servicing schedule is what carries it to the top of the range.
What it costs to replace: plan on $800–3,000 (batteries $100–300 each). Replacing on your own schedule, before it fails, is almost always cheaper than the emergency version. The home maintenance cost calculator helps you set the money aside before it comes due.
OnOtto tracks your robot mower blade swaps age and service history, and warns you before end of life instead of after the flood.
Track your home's systems, free for 30 daysFrequently asked questions
How long does a robot mower battery last?
Three to five years, or roughly 300–500 charge cycles, before it holds noticeably less charge. You see it as shorter mowing sessions and a lawn the mower can no longer finish in one run. A replacement lithium-ion pack costs $100–300 depending on brand, and swapping it is a 10-minute job on most models. Since the rest of the mower lasts 8–10 years, budgeting for one or two battery changes over its life is normal, and far cheaper than a whole new machine.
How often do robot mower blades need replacing?
Every 6–10 weeks during the mowing season for the small pivoting razor blades most brands use, or sooner if you keep hitting sticks and pinecones. A fresh set of three or four blades costs $10–25. Dull blades tear grass instead of slicing it, which browns the tips, invites lawn disease, and forces the motors to work harder, draining the battery faster. Some heavier-duty models use fixed steel blades that last a full season but need occasional sharpening.
Should I bring my robot mower inside for winter?
Yes, in any climate with a real freeze. Store the mower and its charging station indoors, ideally with the battery around half charged, somewhere above freezing. Lithium-ion cells degrade fastest when left in the cold or sitting fully drained for months, so winter storage is the biggest single thing you can do to reach 8–10 years out of the unit. Clean the deck, wipe the charging contacts, and give it a full charge before the first cut in spring.
Are robot mowers worth it long term?
Over 8–10 years the math is closer than the sticker suggests. A $1,500 robot plus one or two $100–300 batteries and a few blade sets runs roughly $2,000–2,500 all in, versus buying and servicing gas mowers over the same span. You trade oil changes, spark plugs, and fuel for battery swaps and the odd cut boundary wire. For small, mostly flat lawns the convenience is real; for large or steep lots, a rider still wins on capacity.