To avoid damage to carriers, as well as the traversing mechanism itself, always be sure the vanes of a vertical blind are tilted to the open position before traversing them.
The photo indicates when a vertical blind is ready to be drawn to the side on which it stacks, and when it is not.
The same applies to privacy sheers.
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.