In which situations is it easier to use a string rather than StringBuilder?

When a small number of string operations need to be performed, or when the operation is performed only once. Creating and assembling a StringBuilder has overhead.

// Simple assignment
string name = "John Doe";

// Several concatenations, but with literals, the compiler optimizes
string greeting = "Hello, " + name + "!";

// Concatenation of a small number of strings
string combined = firstName + lastName;

// Using interpolated strings for small expressions
string formatted = $"User: {userId}, Status: {isActive}";