JavaScript closures are a powerful language feature. They are often quite useful in hiding variables from other code, so that we don’t tread on variable names being used elsewhere. Due to jQuery’s frequent reliance on functions as method arguments, they can also be inadvertently created quite often. Understanding them allows us to write more efficient and concise code, and with a bit of care and the use of jQuery’s built-in safeguards we can avoid the memory-related pitfalls they can introduce.