String vs. StringBuilder

Question

I understand the difference between String and StringBuilder (StringBuilder being mutable) but is there a large performance difference

Answer 1

As a general rule of thumb, if I have to set the value of the string more than once, or if there are any appends to the string, then it needs to be a string builder. I have seen applications that I have written in the past before learning about string builders that have had a huge memory foot print that just seems to keep growing and growing. Changing these programs to use the string builder cut down the memory usage significantly. Now I swear by the string builder.