Let me quickly run you through a scenerio and see if this sounds familiar:
First you take the time to plan out your backup schedule days in advance. Then Friday hits and you stay at the office an extra hour or two late to set your backup to run over the weekend, giving your system all the time it needs to read through every bit of data as it tries to determine what has changed since last weekend’s backup.
If you're like the vast majority of organizations, you are amassing data at an exponential rate, storing it on hard drives that get bigger and bigger every year while maintaining the same performance and speeds. This means that those weekly incremental backups are going to constantly get slower and slower until that single backup window turns into a weekend-long fiasco, jam-packed with aggravating performance issues.