Many people think that wall decals are like stickers as they look similar to the wall stickers, but in reality they are not. The simple logic is if they are one and the same they might have given the same name. If it is not, then they might have different features which make them different from wall stickers. Wall stickers are something which can stick permanently to the walls and there is nothing like peeling the cover once they are applied to the walls. On the other hand wall decals are not permanent and hence are easily removable.
Many manufactures say that wall decals are replaceable. No one can attach the wall decal without breaking it in the middle. So it becomes complicated to attach all the pieces and make it in to a complete picture and to give the look as it is for the first time. Also the adhesive will loose its strength when it is removed and exposed to air and heat. This will disable the decal to stuck firmly to the wall.
Wall decals leave residue on the wall is one of the reasons that makes most of the people stay away from them. Since, they are popular as removable wall decals it is hence clear that they can be peeled easily and hence would not leave any residue on the walls.
The name wall decals does not mean they are meant only for applying on walls. Even though they are made with a view to decorate the walls, as they stick to any plain and smoothly textured surface they can be used on glasses, mirrors, wood, metal, windows, door, and so on provided they are even and not roughly textured. You can also use them for your cars and other vehicles.