Paper corner guards are a material used to protect and reinforce packaging, usually made of cardboard or paper material. They are used to support the corners of packaging boxes to prevent crushing and damage during transportation and storage. The storage period of paper corner protectors mainly depends on the following factors:

1. Environmental conditions: Paper corner guards should be stored in a dry, ventilated environment, away from moisture, open storage, high or low temperatures. Harsh environmental conditions may cause the paper corner protectors to become damp, moldy or deformed, shortening their lifespan.

2. Packaging quality: Paper corner guards should be stored in their original packaging to prevent dust, dirt or other contaminants from adhering to their surfaces. Contaminated paper corner guards may not effectively protect packaging.

3. Frequency of use: If paper corner guards are used frequently, they may wear out faster. Therefore, storage periods may vary depending on frequency of use.

4. Quality and durability: Different brands and types of paper corner guards have different quality and durability. High-quality paper corner guards generally have a longer lifespan.

5. Manufacturing date: Paper corner protectors usually do not have a clear expiration date, but prolonged storage may cause their quality to deteriorate. It is recommended to use newer paper corner guards first to ensure their performance.

Generally speaking, if paper corner guards are stored properly and are not exposed to contamination or harsh environmental conditions, they can maintain quality and performance for several years or even longer under the right circumstances. However, in order to ensure its effectiveness, it is recommended to check the stored paper corner guards regularly and replace them promptly if any problems are found. Also, make sure the paper corner guards are visually inspected before use to ensure there is no obvious damage or deformation.