What should never be done with Dyneema webbing to prevent slippage?

Cutting and retying Dyneema webbing can compromise its structural integrity and lead to slippage. When webbing is cut and then knotted, the knot can create stress concentrations that weaken the overall strength of the material. Additionally, the knot itself can allow for movement within the fibers, increasing the chance of slippage under load. Knots require specific techniques to maintain strength, and while some knots are suitable for certain applications, they may not be appropriate for the unique characteristics of Dyneema webbing, which is designed to maintain its strength in a continuous form.

The other options involve conditions or applications that can affect the webbing's performance, but they are not specifically tied to preventing slippage in the same way that cutting and retying do. For example, girth hitching two slings together can be a secure connection if done properly, and storing in wet conditions or exposing the material to sunlight could degrade the webbing over time but does not directly relate to slippage during use. Thus, maintaining the integrity of Dyneema by avoiding cutting and retying is critical in ensuring its effectiveness in rescue situations.