As you can imagine, the more fragments you have the more of a maintenance issue you have. The lower the number the better it is. The magic number is under 20, but if you are over this then it isn’t the end of the world. You are just in the yellow zone. The fewer fragments you have the quicker that the file can be read. File fragments in and of themselves are not the problem – you will never have 0 fragments. They are just one of the gauges to measure file health (highest I’ve seen was over 300, and that was a rough one!).