The answer to 'retaining wall erosion' is that it is a common problem caused by a variety of factors, including poor drainage, soil erosion, and structural issues. Symptoms can include cracks, leaning, or even collapse of the wall. Solutions can range from simple repairs to complete wall replacement, depending on the severity of the issue.
Homeowners should first inspect the wall for signs of damage, such as cracks, bulges, or missing mortar. They should also check the drainage around the wall to ensure water is properly diverted away from the structure. Minor repairs, such as patching cracks or repairing the drainage system, may be possible for DIY homeowners. However, for more significant issues, it's best to call in a professional landscaping or masonry contractor to assess the problem and recommend the appropriate solution.