File names should be descriptive, but they also must be live within the limitations of file systems. As files are moved from place to place, long or unusual names may become incompatible. A few simple tips:

• Keep File Names Short Just because you can use 64 characters in a file name doesn't mean you should! There are situations where operating systems put together the path name (the full path to the file, such as C:\Users\kmmLO\Documents\TTFileNames.docx); if that path name gets too long it can cause problems. Also, different operating systems have different limitations, so if you pass the file on to others it may cause problems for them.
  
• Do Not Use Spaces in File Names Spaces don't translate well when used on the web, and they may be incompatible with older file systems. Separate words by using capitalization or underscore (TechTip01.docx or Tech_Tip_01.docx).
  
• Don't Use Punctuation The use of periods should be restricted to file extensions (such as .doc or .docx), and you should never use commas or other punctuation marks. Punctuation marks, like spaces, can cause problems when different environments try to interpret their meaning.

In other words: Stick to short file names that contain only letters, numbers, underscores, and a proper file extension.