At what point does using a StringBuilder become insignificant or an overhead?

Question

Recently I have found myself using StringBuilder for all string concatenations, big and small, however in a recent performance test I swapped out a colleague\'s stringOu

Answer 1

From MSDN:

[T]he String class is preferable for a concatenation operation if a fixed number of String objects are concatenated. In that case, the individual concatenation operations might even be combined into a single operation by the compiler. A StringBuilder object is preferable for a concatenation operation if an arbitrary number of strings are concatenated; for example, if a loop concatenates a random number of strings of user input.

I guess the answer is "it depends" - if you're concatenating inside a loop with more than a handful of iterations then a StringBuilder will almost always deliver better performance, but the only way to know for sure is to actually profile.