[Q] Do we need updated Busybox? topic

Let me get straight to it:

Let's say I install a custom recovery, and flash a ROM after rooting and unlocking Bootloader... Do I NEED to install Busybox, and update its binaries, or is it already done in most ROMS? Sprint ROM threads don't seem to specify this, and I wonder why do people even needed this in the past:

[ROOT][5/24]Sprint One Root and Disable System Write Protection