Why you should MOD your Android phone?
- Unlock your device's Bootloader to gain access to the flexibility otherwise unavailable.
- Install a custom Recovery image for your device to flash aftermarket software packages.
- Create full backups of the present or a different state of your phone.
- You can install the latest Android build through a Custom ROM or build a ROM yourself directly from the Android source tree and install it.
- Install the latest compatible Android ROMS with new features that aren’t even available in the latest stock Android yet.
- Create and install custom Kernels for maximum performance and battery life.
- You can use experimental, high efficiency and high performance applications that require root.
- Remove all the bloatware you dont want or even run your phone on a bare-to-the-bones ROM.
- You can increase the battery life of your device using methods which are only applicable if your phone is Rooted.
- You can install and run a full Linux distribution on your phone.
(Link for installing Debian on the "first android phone").
Hopefully one or many of these reasons will convince you to mod your phone, Eespecially after your phone's warranty is over because modding your device will void its warranty.