What potential pitfalls can arise from not properly declaring variables in PHP?

Not properly declaring variables in PHP can lead to errors such as undefined variable notices, which can make debugging more difficult. To avoid this issue, always declare variables before using them in your code by assigning them a default value or initializing them with appropriate data.

// Properly declaring variables in PHP
$variable = ""; // Initializing variable with default value

// Now you can safely use $variable in your code
echo $variable;