Most yorkie owners keep their dogs in a shorter clip then the standard show cut... some shave them very short, some keep them middle length. All yorkies that fit the standard should naturally have a long coat... however, it is very hard to maintain so very few people outside of the show world keep it floor length.
It can take two years or more to grow the coat all the way to the floor.
How often you groom depends on what you want. I keep my yorkies in a medium length type cut and they get groomed every 8 weeks but do need to be bathed in between and brushed almost daily.
If you shave them shorter, you could probably go much longer between groomings.
They are very versatile dogs as far as their hair goes... you can do pretty much anything with them.