There is more data to backup. The number of computer users in the office continues to grow, as does the variety and size of software applications and operating systems. Expanding software storage needs have coincided with drops in the cost of magnetic storage media, causing an explosion of storage capacity on local area networks. This storage explosion translates into longer backup times and the need for increased backup capacity. There are more types of data to backup.
More operating systems are present on networks.
Backing up these disparate systems requires capable backup tools that were not available a few years ago. It has never been easy finding a good time to backup material. The window for nightly backups is shrinking as workers enjoy more flexible work hours, and use modem connections and remote office locations to access data through a wide area network or Internet connections. Change the way you backup. Perhaps you can backup files that have changed on a daily basis, and save full backups for weekend hours.