WiFi keeps dropping out — how do I fix frequent disconnections?

Common causes, roughly in order of likelihood: channel congestion from neighbouring apartment WiFi networks (fix: set a fixed 2.4GHz channel like 1, 6 or 11 instead of auto); two routers on the same network fighting each other (a genuinely common apartment issue we see often); outdated router firmware; or an actual ISP line fault (test by connecting via Ethernet — if it still drops out wired, it's not a WiFi problem).