mac maintenance - is HD defrag necessary?, mac audio maintenance Options

[Ged]

I'm a recently migrated PC user and am new to audio recording using an ibook. When working with audio on a PC it's absolutely essential to regularly defragment the computer's hard drive (to ensure peak performance i.e. processor speed etc.). I'm wondering if mac systems require the same kind of maintenance when working with audio and, if so, which applications/programs would you suggest I use to perform this task (or any other related maintenance task)?

Cheers

G