What are common issues with using single and double quotes in PHP?

Common issues with using single and double quotes in PHP include escaping special characters, interpolation of variables within double quotes, and readability concerns. To solve these issues, it is recommended to use single quotes for string literals that do not require variable interpolation or special characters, and double quotes for strings that need variable interpolation or special characters. Example PHP code snippet:

// Using single quotes for string literals
$name = 'Alice';
echo 'Hello, ' . $name . '!'; // Output: Hello, Alice!

// Using double quotes for variable interpolation
$age = 25;
echo "I am $age years old."; // Output: I am 25 years old.

// Escaping special characters
$quote = "He said, \"Hello!\"";
echo $quote; // Output: He said, "Hello!"