Refurbished smartphones: what tests guarantee their reliability?

In the refurbished smartphone market, quality grades play a key role: they determine a device’s value, perceived reliability, and the level of trust from end users.
Whether for consumers or professionals, these grades come into play at various stages: when buying a second-hand device, through specialized marketplaces, or within trade-in programs led by retailers, carriers, or OEMs.

For professionals, testing is essential to offer reliable, compliant, and durable products, fully aligned with the expectations of the circular economy in the electronics sector.
To ensure a refurbished smartphone provides a smooth and secure user experience, each device undergoes a series of 30 to 60 quality checks, also known as control points. The purpose of this rigorous process is to assess both aesthetic and software performance, in order to assign an appropriate grade before the product is officially reintroduced into the secondary market.

💡 So how does the testing process work? Which tools and software are used, and for what purpose? What kind of diagnostics are run on devices? This article will answer all your questions.

What tests are performed on a refurbished smartphone?

Once devices are received and stored, the first steps in the refurbishment process involve verifying their proper functionality using mobile diagnostic software. These tools quickly detect any hardware or software malfunctions. Based on the results, certain components may be replaced — for instance, a battery with less than 80% capacity.

After the technical inspection and any necessary repairs, each smartphone is visually evaluated to assess its cosmetic condition and assigned a grade. This rigorous quality control protocol ensures that every device refurbished by Dipli’s partners is fully prepared for a second life on the market, without compromising on quality.

1. Functional tests: ensuring smooth and secure usage

Functional tests are carried out according to a strict set of specifications defined between the refurbisher and the smartphone supplier. These procedures analyze all essential components of the device to verify technical integrity and compliance standards (spare parts conformity (especially after a repair), presence of CE marking or an equivalent certificate of conformity, complete erasure of all previous user data, etc.).

Below is a non-exhaustive list of quality checks that can be performed on a refurbished smartphone:

• Rear camera,
• Front camera,
• Phone call,
• Battery and charging connector,
• Bluetooth,
• Home button,
• Mute button,
• Power button,
• Volume buttons,
• Proximity sensor,
• Earpiece,
• Phone status,
• Back panel,
• Front panel,
• GPS,
• Speakerphone,
• iCloud,
• iCloud disabled,
• IMEI,
• Flashlight,
• Microphone HP,
• Microphone,
• Unlocked operator,
• Jack,
• Network,
• Touchscreen,
• Keyboard test,
• Vibrator,
• Front window,
• Wifi.
  
  

2. Aesthetic testing: assessing the visual condition of the device

Once technical tests are successfully completed, each smartphone undergoes a rigorous aesthetic evaluation. The objective is to determine the level of visible wear based on standardized criteria: presence of scratches or impacts, condition of the front panel, back cover, frame, and ports, etc.

Each device is then assigned a grade. At Dipli, the following grades are used for distribution programs:

• Grade CPO: like-new condition,
• Grade A: excellent condition, minimal signs of use,
• Grade B: good condition, some visible but non-disruptive marks,
• Grade C: more pronounced wear, fully functional but visibly used.

After grading, partners must perform a complete cleaning of the smartphone, including the front and back surfaces, casing, and charging and audio ports. This attention to aesthetics is crucial to meet the expectations of B2B buyers, telecom operators, and distributors aiming to offer appealing refurbished products.

Following this series of functional and aesthetic tests, the devices are ready to be shipped to customers.

As a Social and Solidarity Economy (SSE) company, Dipli is committed to environmental protection. We are proud to help make the tech industry more sustainable and circular. In 2025, we achieved the following results:

📱 Over 800,000 devices were given a second life through Dipli,
🪨 62,480 tonnes of raw materials saved,
♻️ 52,100 kg of e-waste (WEEE) production avoided,
💧 18,533,728 m³ of water conserved.

Our mission is clear: to give every electronic device a second life and thus double its lifespan. We are fully committed to developing solutions for professionals in the sector.

Are you looking to launch a trade-in program or improve the distribution of your refurbished products?

Dipli simplifies the second life of electronic products.

An all-in-one tool for distributors, leasing companies, telecom operators and companies to manage the entire value chain in one place.

The platform connects the electronics industry to secondary markets; simply and securely. Trade-in and return management, refurbishment, omni-channel purchasing and distribution: Dipli covers and simplifies all stages of the circular economy.