While there is little dispute among IT professionals regarding the impact of disk fragmentation on system performance, no independent guidelines exist to recommend the frequency of defragmentation across an infrastructure. Some IT professionals use defragmentation as a measure of last resort, defragmenting only after system performance has sufficiently degraded to make its impact directly noticeable to users. Others proactively schedule disk defragmentation regularly, with the intent of eliminating the gradual accumulation of fragmented files.