All plaster walls will crack over time due to normal house settling and expansion and contraction from temperature and moisture changes. Small, thin hairline cracks are generally not serious and are mostly a cosmetic issue. However, larger or more significant cracks can indicate structural problems.

Here's how to tell the difference:

• Cosmetic Cracks: Cracks that are 0.5 cm (0.2 inches) or thinner are typically cosmetic.

• Structural Cracks: Cracks wider than 0.5 cm, excessive or deep cracks, multiple cracks in the same area, or cracks that span around corners can signify a structural or foundation issue. Cracks along the joints where walls meet the ceiling also warrant attention.

For cracks wider than 0.5 cm, structural repair is needed. If a crack is 2.5 cm (1 inch) or wider, or if you notice any signs of a structural problem, it is best to contact a plaster repair professional to assess the damage.

Although they are used for similar tasks, spackle and joint compound are not the same. Joint compound, also known as drywall mud, consists of limestone and gypsum and is primarily used for large-scale projects like taping and finishing seams on new drywall. Spackle is composed of gypsum and binding agents, making it a thicker compound best suited for small wall repairs like filling nail holes or cracks, as it dries quickly and is easy to sand. For small repairs, either product can be suitable. However, you can use joint compound for small jobs in place of spackle, but you cannot use spackle for large-scale taping and mudding projects.

Whether you can reuse a drywall anchor depends on its type, material, and how it is removed. Plastic anchors, such as expansion or self-drilling types, are generally considered single-use because they are designed to expand and are likely to break or become deformed upon removal. Metal anchors, like toggle bolts, are more durable and can often be reused if they are not damaged during extraction. However, with toggle bolts, the toggle mechanism can fall inside the wall when the bolt is removed, making it difficult to retrieve. If an anchor is damaged or must be cut for removal, it cannot be reused regardless of its material.

Technically speaking, you can use drywall primer over plasters. However, oil-based primers work the most effectively on wall plasters. Meanwhile, water-based primers work just as well with drywalls. Nowadays, there are also universal primers suitable for drywall and plaster. Overall, you will be fine as long as you are using a trustworthy brand.