+ Use correlation ids on more complex applications so you can track more than a single failed call into an application. Getting an error like "this thing fell

+ Use correlation ids on more complex applications so you can track more than a single failed call into an application. Getting an error like "this thing fell over because of a number parsing error" might not be very useful when you can't recreate it. With correlation, you then realise that the user did something specific beforehand and then the cause is more obvious.