Never let go of a cord until you know it has come to rest. Shades and blinds with modern retractable mechanisms typically use control cord assemblies. These incorporate hard connectors (pictured) capable of damaging delicate components on impact.
Additionally, an unchecked recoil may cause the cord to jump one or more contact points inside the headrail. Some are inaccessible, and may require costly factory repairs to restore functionality.
With traditional cord-lock mechanisms, the cord should not be released until its “catch” is engaged. This prevents the bottom-heavy shade from crashing down onto the sill.
For long life, correct operation of functional window coverings is the most important factor. But they will eventually fail. When they do, ADVANCED ON-SITE provides a full compliment of drapery and shade services, including repair.