Going back 35 years or so (an eon in computer industry time) all computer system tasks were performed manually. It caused system administrators to work insane hours, for many of these tasks, such as defragmentation, backup-and-restore, disk integrity checks, disk error repairs and the like, had to be performed when users weren't on the system. That meant nights and weekends spent camped out in the computer room, and ask anyone who was there: it was no fun.
In the early nineties, scheduling such tasks began to appear, which for these beleaguered system administrators was fantastic news. Tasks such as defragmentation could be scheduled to run at certain times, when users weren't on the system, and when the administrator was thankfully home asleep. As time went on, anti-virus software came on the scene and virus scans could also be scheduled.
As the century turned, however, life did not become easier for the system administrator. The shift was fully made from larger systems such as mainframes and mini-computers to PC servers and workstations, which meant many, many more systems to implement, control, and debug. Legacy applications had to be ported from older architecture which was at best difficult and at worst impossible. The number of disks to which data was written and saved proliferated like hamsters, and soon new disk disaster protection technology (RAID) appeared which complicated storage technology even further. Recently developments such as virtualization, NAS and SAN have moved things up yet another echelon.
As technology has became more complex, business has not slowed down. In fact, due to the Web and globalization, the number of sites having to run 24X7 has increased dramatically. It has now reached the point where time windows to run scheduled tasks when users aren't on the system are becoming small or nonexistent.
IT time also now comes at a premium. Numerous technical pundits are now pointing out that we have long passed the point that scheduling has become outdated. Due to today's frantic IT environments, and also due to the growing number of under-qualified personnel to handle them, as many tasks as possible need to be fully automatic. Many technologies, including defragmentation, are now available to be fully automatic and non-intrusive to users on the system. IT departments should gain themselves some time and do all they can to investigate and implement such fully automatic solutions.