As a real estate appraiser, there are three primary approaches to property valuation that are used in the industry. Understanding these approaches is critical to accurately assessing the value of a property, whether for tax assessments, mortgage lending, or other purposes. Here are the three approaches to real estate appraisal and when they might be used:

1. Sales Comparison Approach: This approach is used to estimate the value of a property by comparing it to similar properties that have recently sold in the same area. The appraiser will make adjustments to account for any differences between the subject property and the comparable properties, such as differences in location, size, and condition.
2. Cost Approach: This approach is used to estimate the value of a property based on the cost to replace it. The appraiser will consider the cost of the land, construction costs, and depreciation to arrive at an estimate of the property's value.
3. Income Approach: This approach is used to estimate the value of a property based on its potential income. It is typically used for investment properties and involves estimating the property's potential income, deducting expenses, and arriving at a net operating income figure. This figure is then used to estimate the property's value.

Each of these approaches has its strengths and weaknesses, and the choice of which approach to use will depend on the type of property being appraised, the purpose of the appraisal, and other factors. As a real estate appraiser, it is essential to understand these approaches and be able to apply them accurately to ensure that clients receive an accurate and reliable valuation of their property.