If you’re like me, you’ll turn to the second-hand market to save money when buying tech goodies like Wi-Fi routers. While new routers can cost a pretty penny, buying those same models used could net you significant savings. But could buying a used router actually pose a hacking risk?

Used Routers Generally Do Not Present a Security Risk

You’re likely worried that hooking up a used router to your network could open a backdoor for hackers. After all, your router is the access point between your ISP-supplied modem and personal devices, so any compromises in the network could pose a serious security risk.

While that’s a valid concern, the truth is that routers store little data on them and aren’t capable of doing much harm, even if the previous owner customized the firmware. Plus, the vast majority of sellers on online marketplaces aren’t techies who like to tinker—they’re probably selling their old routers because they recently upgraded and want to make a quick buck instead of leaving the router to collect dust.

Performance Didn’t Deteriorate, but the Router Might Be Obsolete

A router’s performance deteriorates at a very slow pace, if at all, even after many years of daily use. A router is essentially a tiny computer for your internet connection, and like most computer parts, routers either work or don’t work correctly; your internet bandwidth will remain within spec regardless of its condition. It’s worth noting that major firmware updates can slow a router down significantly, but that’s rare. Instead, new firmware is more likely to speed them up, if anything.

However, just because the performance of a used router hasn’t slowed down doesn’t mean that it isn’t obsolete. While the router stayed the same, all other devices around it and your Internet Service Provider’s (ISP’s) network have continued to evolve and improve. For instance, the new Wi-Fi 7 standard is five times faster than Wi-Fi 6, uses the 6 GHz band, and has incredibly low latency. Newer routers also have improved security features, such as WPA3.

Because of how fast things change in tech, I can only recommend buying a router that isn’t more than two years old. Even if you don’t care about maximizing your bandwidth and low-latency Wi-Fi, you should get a router with WPA3 at the very least.

Before buying a router, you should also double-check that it’s compatible with your ISP-supplied modem. While they’re mostly interoperable, there’s always a small chance that your modem won’t work with your newly bought router. Check what routers are compatible with the modem before buying.

If you’ve already bought a cheap router at a garage sale, you should probably look up the model online before hooking it up to your network. Make sure that it has received relatively recent firmware updates (6–12 months ago at most), and check the specifications sheet to see if it has sufficient bandwidth and supports the latest security features, which is WPA3 at the time of writing.

Watch Out for Physical Damage

Even if the router is only a few months old, you should inspect it for any signs of physical damage. Broken antennas, stuck buttons, and bent pins in Ethernet ports can all compromise the functionality of your router. Considering new routers aren’t that expensive to begin with, and there’s an abundance of used routers, you shouldn’t waste your money on a broken device.

Do a Factory Reset and Flash Stock Firmware Just to Be Safe

Before you hook up the network cables to the used router you just bought, you should perform a factory reset to wipe the preconfigured settings, such as the Wi-Fi password and access point name. Most routers have a dedicated reset button that you’ll have to press and hold for 10–15 seconds using a thin tool, such as a piece of wire or toothpick. You’ll know that you were successful if the LEDs on the router turn off or flash a few times. If that didn’t work, check the router’s user manual on the manufacturer’s website, as the steps can vary depending on the make and model.

Once it’s back to factory settings, you can connect your Ethernet cables and hook it up to your modem. But we’re not done just yet, as we still have to check the firmware to make sure it’s stock and up-to-date. The easy way to do it is to download and install the manufacturer’s mobile app, assuming your router is compatible with it. If not, you can type in the default gateway in your browser and log in to the router settings. Consult the user manual or manufacturer’s website to find the default gateway, username, and password for your model.

Once you’re in the router settings, look for any options that mention something along the lines of “firmware” or “update device.” When you track down the firmware version, go to the router model page on the manufacturer’s website. Open “Support” or “Download,” and make sure that your router uses the latest firmware version. If it doesn’t, update the firmware automatically by clicking the update firmware option.

If the router is using custom firmware that isn’t listed on the manufacturer’s website, you should download the latest official version and flash it through the router settings via your computer or laptop. There’s a low chance that you’ll encounter custom firmware and have to do this, but it’s better to be safe than sorry.

Only Consider Slightly Used Routers at a Good Price

Used routers are generally safe to buy, but that doesn’t necessarily mean that you’re getting a good deal. Many routers you can find on eBay, Facebook Marketplace, and Craigslist are old and don’t even have the model name included in the product listing.

I recommend that you only buy a router whose model you can identify. And when you do, check its retail price and make sure it’s not discontinued, as it won’t receive new firmware updates if it is. If the used router is at half the price or lower, then it’s a decent deal. It’s an effortless way to save $30–50 without having to make any sacrifices.