By Design of Your Life
Larger pieces (more expensive) should be neutral so you can decorate with color or for seasons with smaller (less expensive) pieces.
Different sizes and heights to help with layering.
Sets are already coordinated and can give you a variety of sizes. Don't forget you can split them up!
Shades of green, blue, white, and red are popular seasonal colors so you can reuse them throughout the year.
1 Vase: Spring Summer Christmas