Avoid unmaintainable code
The maintainability index is calculated by using the following metrics: lines of code, program volume, and cyclomatic complexity. Program volume is a measure of the difficulty of understanding of a type or method that is based on the number of operators and operands in the code. Cyclomatic complexity is a measure of the structural complexity of the type or method.
A low maintainability index indicates that a type or method is probably difficult to maintain and would be a good candidate to redesign.