Plaster is known to last up to 100 years. It is noise resistant but also insulates well. When plaster wall becomes old and cracked up, it is worth the effort to repair them and save up on the cost. Sometimes you need to sand out the walls and repair the minor damages. Ensure that you fix the small holes and cracks. You do this by smoothing them with spackle using your fingers.

Give the patches time and make sure there are no wet spots on the wall. One thing you should note is that plaster will take some time to dry. Once the plaster is dry, use a 60 or 80 grit sandpaper to rub against the surface of the wall. Ensure that you level the bulges while using a cloth for wiping of the dust on the walls. Apply oil based primer on the walls and after 24 hours paint the walls.