Disc brake anti rattle clip question

Just thought I would ask if anyone knows whether or not the anti tattle clips are necessary on the outside of the front disc brake pins that hold the caliper and brake pads in place. Seems not too many people sell them and they are expensive plus when I removed the front calipers and pads from the donor car I purchased the anti rattle clips were not there. I appreciate any feedback I can get on this.
Thank you
Author: Cud@