Installing a custom firmware on your router gives you more control and longer support than the stock firmware.
How to Install OpenWRT Firmware on NETGEAR WNR3500L
Router XDA Developers
OpenWrt
OpenWrt is often ideal for older or cheaper modems to provide lots of extra, and up to date, features and security patches - Check when you buy, that a modem is OpenWrt
DD-WRT vs. OpenWrt: Which open-source router firmware should you pick?
How to Install OpenWRT Firmware on NETGEAR WNR3500L
OpenWRT vs dd-wrt vs tomato- Which is the best router firmware?
OpenWrt, an open source alternative to firmware for home routers
Thomas Bain on LinkedIn: Widespread Cisco IOS XE Implants in the Wild - Blog - VulnCheck
Koji Wi-Fi ruter uzeti?, Strana 98
OpenWrt: How It Works, Challenges and Alternatives
Glass Wings diaspora*