Updated: Feb 10, 2021
Although dried flowers last a long time, they don't last forever. Care must be properly given them so they last you a year or few years.
Keep them from direct sunlight, it's best to display these beauties indoors, away from direct and bright light, which cause the colors to fade and make them brittle.
Please remember, they do not need water. Moisture and humidity are its number one enemy. Keep your arrangements away for drafty doorways or windows too, moisture in the air will make your dried and preserved flowers develop mold.
If they need cleaning, use canned air, or your blower on its lowest cool setting. Alternatively, a feather duster may be useful but risky for small dried brittle leaves or tiny flowers.