For a big anniversary, couples often replace their engagement ring with a grander model. When shopping now, ask jewelers if they'll accept this purchase as partial payment on a later ring. Both Tiffany & Co. and Jeff Cooper will apply the full retail purchase price toward another ring (that's at least double the value) for as long as you own your original one.

2.5-carat emerald-cut diamond with 1 total carat emerald-cut side stones in platinum ($38,625) and 1-carat round diamond in platinum ($9,375), Jeff Cooper Designs at Robbins Bros.; 800-610-7464.