Agreed. Small percentages of fragmentation won't cause any performance decrease that the user can notice, but once you start getting into double-digit percentages of fragmentation, you will notice an overall "sluggishness" start to set in. There's no single schedule for defragging, because (as nizzy1115 alluded to) fragmentation results from adding, deleting, and modifying files; the more of this you do, the more quickly your drive will become fragmented.
DMR 152 Wombat At Large Team Colleague
DMR 152 Wombat At Large Team Colleague
DMR 152 Wombat At Large Team Colleague
DMR 152 Wombat At Large Team Colleague
DMR 152 Wombat At Large Team Colleague
DMR 152 Wombat At Large Team Colleague
DMR 152 Wombat At Large Team Colleague