using make for backups

[Payal]

Hi all 
Daily I take backup of a folder like this.
tar -czf d-`date +%d%m%y`.tar.gz designs/
The size comes ~ 2Gb of tar ball.  
There are tens of folders/sub-folders inside design/. 
I observed that many days none of the files in design folder are changed or are 
added/deleted and 
I am wasting resources making the tar-ball daily.

Can I use make to take backups if files inside design/ are 
modified/added/deleted or do I rather
depend on tar to figure it out?

With warm regards, 
-Payal