Buying a Used Robot: What to Check Before You Pay

Buying a used robot, whether an educational model, an articulated arm or a mobile platform, is a bit like buying a second-hand car. The listed price says nothing about the machine’s real condition. Here is what to check before committing.

Battery and power condition

On most robots, the battery is the part that wears out fastest and is often the most expensive to replace. Ask for the battery’s age, the approximate number of charge cycles, and if possible a load test. A swollen battery, or one that only holds a fraction of its original range, should be negotiated into the price, or even cancel the sale if no replacement is available.

Spare parts availability

A robot that works today but whose manufacturer has stopped producing parts becomes a bet on the future. Before buying, check whether the motors, circuit boards and sensors specific to the model can still be found, new or used. Some models widely used in schools or workshops have an active community that makes compatible replacement parts, which changes the picture considerably.

Software and licences

Some robots, particularly in the educational or industrial space, depend on proprietary software tied to a serial number or a user account. A robot sold second-hand without a valid licence transfer can end up locked after an update or an account change. Always ask whether the licence is transferable and check the manufacturer’s terms.

Usage history

A robot that worked eight hours a day in an industrial setting does not wear the same way as one that sat on a shelf. Ask the seller about the context of use, the frequency, and any repairs already carried out. Signs of disassembly, or screws replaced with a different model, are often a good clue that something was worked on in the past.

Test before you commit

Whenever possible, ask for a live demonstration rather than a pre-recorded video. A quick test makes it possible to spot abnormal mechanical noises, jerky movements or error messages that do not always show up in a simple photo.

These checks take a bit of time, but they avoid most bad surprises. On Robotmarkt, the goal is precisely to give sellers the means to present this information clearly from the listing itself, so this verification work is faster for both sides.