1. Boost your Phone speed & Battery Life.
2. Remove Pre installed crap ware like System Apps.
3. Remove Bloatwares, Apps like Facebook, Chrome Keep sucking your Ram & battery by running in background So, Among the smartphone geek crowd, applications like these are referred to as “bloatware:” they do nothing but bloat the software by existing as unnecessary applications.
4. Tweak your phone like : Increase Video streaming speed, Increase Wifi Speed, Increase SIM detecting Speed, Increase SD read/write speed.
5. Most Important & Best part, Install Custom Kernel & Custom ROMS ( I will explain about it in Installing Custom ROM section Custom ROM section )
6. Finally, Truly Own your Device, Make it appear in the way you want.