[gentoo-user] rsync to a USB stick

[Mick]

Hi All,

I run:

 rsync -a -l --delete -v /mnt/Business_dir /media/sdf1

to back up a directory from a PC to a USB stick.  However, from a cursory look 
this *seems* to copy the complete directory (every time I run it) and 
overwrites the USB stick.  Carrying on like this it will life-expire the USB 
stick in no time, plus it takes ages to complete as it copies over every 
single file again and again.

Is there a cleverer option I can add to rsync so that it only copies new 
files, overwrites older versions of the same and only deletes any files or 
directories that have been deleted from the source directory?
-- 
Regards,
Mick