Second-Hand Laptop Checklist: What to Test Before You Buy
A used laptop can be a really good deal, but the problems that cost money are the ones you can't see in photos. Ten minutes of testing in front of the seller can save you a lot of regret. Here's what I'd check, roughly in the order I'd do it. Most of it needs nothing but the laptop itself.
The keyboard
Open the Keyboard Tester in the browser and press every key. A key that doesn't light up is faulty, and keyboards are a surprisingly common repair on used machines. Hold a few keys at once too, to see how many presses it can read.
The screen
Look for dead pixels, bright patches, cracks and uneven backlight. Open a plain white page, then a plain dark one, and scan the whole panel. Check that the brightness keys work. Then open and close the lid slowly. The hinges should feel firm, and the picture shouldn't flicker as it moves.
Battery health
On Windows, open Command Prompt and run powercfg /batteryreport. It creates a report comparing the battery's original capacity with what it holds now. On a Mac, open System Information and look under Power for the cycle count and condition. A tired battery isn't a dealbreaker, but it's a good reason to negotiate.
Trackpad, ports and charger
Click and tap everywhere on the trackpad, corners included. Plug something into every USB, HDMI and audio port. Make sure the charger sits firmly and the laptop actually charges.
Camera, mic, speakers and wireless
Record a short clip with sound and play it back. Connect to Wi-Fi, and pair a Bluetooth device if you have one handy.
Specs and storage
Open the system information page and check that the processor, memory and storage match the listing. On Windows, a free tool like CrystalDiskInfo shows how healthy the drive is.
Locks and ownership
This one catches people out. Make sure the laptop isn't tied to the previous owner's Microsoft or Apple account, or to a company management lock, and ask the seller to sign out in front of you. Ask for the original invoice, check the serial number on the maker's warranty page, and get a written receipt.
A return window, if you can get one
Shops and some sellers offer a return period. Get it in writing. It gives you time to find the faults a quick test might miss.
If the seller won't let you test anything, that tells you something as well.