"Just restart your router" is the first thing anyone says when your Wi-Fi drops. Sometimes it even works, for an hour. Then the connection drops again and you're back where you started. That's because a restart only clears a symptom. It doesn't touch whatever's actually causing the drop.
What's really going on
Most home routers juggle three jobs at once: talking to your ISP over the fiber line, broadcasting Wi-Fi to every device in your house, and managing traffic between all of them. A drop usually comes from one of these three places, not all of them, which is why generic advice rarely fixes it for good.
Channel congestion is the most common culprit in dense apartment buildings. Your router might be broadcasting on the same Wi-Fi channel as several neighbors' routers, and every device is quietly fighting for airtime. Overheating is the second most common cause, and routers tucked into cabinets or stacked next to other electronics run hotter than they're rated for, with performance degrading quietly before failing outright.
How to actually diagnose it
Before changing anything, figure out where the drop is happening. If only Wi-Fi devices lose connection but a device wired directly into the router stays solid, the problem is in the wireless broadcast: channel congestion, interference, or an outdated firmware radio driver. If everything drops at once, including wired devices, the problem is upstream in your ISP connection or the router's hardware.
Fixes that actually last
Switch your Wi-Fi channel manually instead of leaving it on auto, since auto-select doesn't always pick the least congested option. Give your router breathing room, since a few inches of open air on every side makes a real difference in summer heat. And keep firmware updated, since manufacturers regularly patch the exact kind of stability bugs that cause random drops.