Plaster walls are pretty known for being thick and brittle so if you don’t install your shelves properly, it can fall anytime. To install your shelves, always use the type of right installation tools like the screws and the driller. Also check the length and the height of the shelf. When you’re putting them on plaster walls, your main challenge is to not drill on incorrect places because the wall is pretty brittle and it could affect the rest of the surface