I use Diskeeper version 6. This has the nice sceduling features that you desire. There is also a "set it and forget it" setting, but I would advise that you be careful how you use this. I eventually disabled the scheduling and automatic defrag in favor of manual defragging. Diskeeper 6 is ideal for an "always on" machine, but I like to have it out of my way when I am on the machine, if you follow me. 😀