Bowie Bailey wrote at about 14:38:26 -0400 on Thursday, April 24, 2014:
 > Think of incremental backups this way...
 > 
 > Pros:
 > 1) They finish running quicker.
 > 
 > Cons:
 > 1) They can miss backing up files in certain circumstances
 > 2) They cause the same data to be transferred multiple times.
 >      - Each incremental will transfer all the same data as the previous 
 > one plus any new changes
 >      - The next full backup will also need to transfer all of that data 
 > again.

Not quite.

Only data changed/added since the previous level incremental needs to be
transferred.

So technically, if you have infinite levels of incrementals, then
each changed/new file is transferred only once so there are no extra
transfers beyond what all fulls would require.

In reality, you want to have a limited number of levels (cycling back
to the full), since having more levels of incremental will cause
reconstruction of the latest backup to take longer since all the
previous levels back to the full need to be scanned -- in particular,
all the attrib files need to be read to see what files may have been
deleted... This reconstruction is needed not just when you restore but
every time you back up so that changes can be identified. In
particular, it is *not* sufficient to just look at the previous
incremental level to determine what files have changed.

The bottom line remains the same. If your bottleneck is bandwidth,
then do all fulls.

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