<p>^^ The software will typically only save ‘updated’ files. Once the initial backup is done the subsequent incremental backups will typically be quick for most people. You should also be able to decide what to backup so for example, you don’t need to backup all the cached internet pages in IE/Firefox. Check the particular backup app to see what it actually does but an incremental backup is a very basic feature. There’s no need to save what’s already been saved.</p>