I have a few custom UIViewControllers in my app which need to know the string returned of an NSDate. I could copy and paste the same code between these classes, but that's obviously terrible practise. It's also probably not good to put it in 1 class as a method, then have another class add this class to take advantage of it's method. It seems like a messy thing to do. So what would you recommend i do?

To clarify - I need a method which is given an NSDate and returns a string, for use in several other classes.