Listen we all have different thoughts on this idea. I am not saying your way or mine is the better way or not, just another way of doing it.
Well if you want to keep that drive going longer I say keep it defrag, you can do it everyday and I've been doing that for years with no problem. Or do it once a week if you like. The longer to keep it fragmented the longer is going to get sluggish.
O&O is a great product, but MFT (master file table) file system needs to be check regular for fragments. Diskkeeper pro does a good job in that department as does O&O does for clusters and other things.. I use both, which can be installed together as one would not be installed without integration with MMC though.
Default Windows XP Pro defrag the one that runs in dos NT window is just fine. Don't forget to run chkdsk c: /f also for those bad sectors if any.
I just recommend daily has a habit.... Since Windows 3.11, Windows for Workgroups 3.11, Windows NT 3.51/4.0, NT Server, Windows 95, 98, ME, 2000 Server, 2000, XP, Server 2003, MCE 2005
The old 2000 Pro, Server, Advance Server get's more fragmented and doesn't really get defragment completely. This is my opinion from experience using these OS Servers...