Wallpaper is something that you will find in many older homes. Even today, many appreciate the look of wallpaper that is well maintained, but there might be problems hiding behind it.
For example, wallpaper might hide cracks or holes behind it, or even worse, there might be mold growing. If moisture is trapped behind the wallpaper, this provides a perfect breeding ground for mold, and it will be hard to spot. If you are buying a home where there is wallpaper installed, you might want to take the extra precaution to use an electronic mold spore detector to make sure there is no hidden mold growth.
If you decide to install wallpaper in your home, it is important that you install it properly, or else it might detract from the appearance of your interior. Once wallpaper has been installed improperly, usually the only fix is to rip it off and start over.