Question about large square quilt rulers
I bought a 15" square quilting ruler last week with a 50% off coupon. The next day I had an opportunity and bought a 20.5" square ruler also at 50% off. Someday I plan to make a quilt with 18" block so am glad to have the larger ruler. Is there a reason I should keep the 15" square since I have the larger 20.5"? I am not a quilt expert, but have made a few quilts and want to make more now that I am retired. Do any of you have and use these sizes or is it overkill to have both?
Thanks
Renea