When Should You Replace Robotic Mower Blades? (The Real Answer)

Every brand publishes a different blade-life estimate. Husqvarna says 4–6 weeks. Worx says 2–3 months. Gardena says "check monthly." The honest answer: it depends on your lawn — but there are three signs that beat any calendar.

Sign 1 — Grass tips look frayed, not cut

Sharp blades slice. Dull blades tear. Walk the lawn the morning after a mow — if tips look white and shredded instead of clean green, the blades have rounded over.

Sign 2 — The mow takes longer than it used to

Most robots adjust their schedule based on workload. If your mower started staying out 30+ minutes longer per session with the same lawn, it's compensating for dull blades.

Sign 3 — Higher-pitched cutting sound

Fresh blades produce a soft "whoosh." Worn blades produce a thinner whine because the motor speeds up to maintain torque. Once you've heard the difference once you'll never miss it.

Rough rule by lawn type

• Clean, level lawn (no debris): every 6–8 weeks
• Average suburban lawn: every 4 weeks
• Sandy soil, near gravel, or with pine cones: every 2–3 weeks
• After hitting a stick or stone: check immediately

A pack of three blades costs less than half a tank of fuel for a petrol mower — there's no good reason to push them. Worn blades brown the lawn and overwork the cutting motor.