Why install a custom ROM?
A custom ROM is a community-built version of Android you flash in place of the one your phone shipped with. People do it for a handful of very practical reasons — here are the big ones, and how to tell if it's worth it for your device.
Get a newer Android version on an old phone
Manufacturers stop shipping major Android updates after two or three years. A custom ROM like LineageOS or crDroid often runs a much newer Android version on the same hardware — so a phone stuck on Android 11 can run Android 14, 15 or beyond, with the newer apps and features that come with it.
Keep getting security updates after end-of-life
Once your phone is end-of-life the manufacturer stops patching it, and known vulnerabilities go unfixed. Actively maintained custom ROMs ship regular security patches for years longer, so an otherwise-abandoned phone stays safe to use day to day.
deGoogle your phone for privacy
Privacy-focused ROMs such as GrapheneOS and /e/OS let you run Android with little or no Google — no Google Play Services tracking in the background, or a privacy-respecting replacement (MicroG) instead. If you want a deGoogled phone without buying a new one, this is the usual route.
Remove bloatware and get clean, stock Android
Carrier and manufacturer skins pile on apps you can't uninstall. Most custom ROMs ship close to vanilla, AOSP-style Android — no bloatware, no duplicate apps, lighter on resources, and often noticeably faster on older hardware.
Keep a working phone out of the bin
A phone that no longer gets updates is otherwise perfectly good hardware. Flashing a custom ROM extends its useful life by years — cheaper for you and a lot less e-waste.
Is it worth it for your phone?
It depends entirely on whether anyone maintains a ROM for your exact device. Search your phone to see every custom ROM that supports it. Flashing does take some effort — unlocking the bootloader, a custom recovery, then installing — and it can void warranties, so read the guides and back up first.
New to the jargon? The glossary explains bootloader, recovery, GApps, vanilla, MicroG and the rest.