Wallpapers can often lead to issues during installation:

1) One common problem is that the adhesive may come off, the pattern may not be evenly aligned, and the seams might turn yellow. This usually happens because most of the workers in China are not professionally trained, leading to a lack of skill and consistency. Additionally, many workers don't fully understand the properties of different types of wallpaper, which contributes to problems like glue coming loose, uneven patterns, and discolored seams.

2) To prevent these issues, here are some important steps to follow:

1) Always use professional tools such as roller machines, brushes, and sponges. These tools help ensure a smooth and even application of the adhesive.

2) Workers should have a good understanding of the wallpaper's characteristics. For example, when installing paper-based, diatomite, or textured wallpapers, it’s crucial to avoid leaving excess glue in the seams. If any glue remains uncleaned, it could cause the adhesive to fail over time or result in yellowing around the seams.

3) When working on corners, use specialized edge banding glue to prevent cracking and maintain a neat finish.

4) Make sure the entire process is done carefully and neatly. Proper alignment and attention to detail will significantly improve the final look and durability of the wallpaper.