The less your swap space is used, the better off you are, and zero swap usage is ideal. The situation you describe, where swap is totally unused, is a good thing.
Think about it - operations within RAM are orders of magnitude faster than I/O operations to/from the hard drive, and the only time swap would get used is if you push RAM past 100% capacity and it is forced to write out memory pages to the disk. This is very inefficient, and you want to avoid it as much as possible. -- J.W.