Tables with random data modification

Tables with clustered indexes that experience many inserts, updates, and deletes over time tend to lead to data pages that are approximately 70 to 75% full. This can lead to performance degradation in several ways:

Once the fragmentation starts to take its toll on application performance, you need to perform maintenance. If that requires dropping and re-creating the clustered index, you need 120% of the space occupied by the table.

IF space is unavailable, maintenance becomes more complex and takes longer. The best, and often cheapest, solution is to add enough disk capacity to provide room for the index creation.