When you may access a file multiple times, the effort required to do so is greatly simplified by naming the file to facilitate finding it when needed. Success is largely determined by two attributes of the file name: uniqueness and meaningfulness. The name must be unique enough that you aren’t presented with a passel of candidates to choose from when you try to search for it. The name must be meaningful, so that you can enter successful search criteria. I think we have all seen the downside of these attributes being handled poorly, when we search for information on web search engines. Better results are achieved with well-named and well-tagged documents
Files used in the course of running a business are even more critical to be described properly as it can cost valuable time and money to access them. There is a site where they have posted and discussed this very question at: http://www.whatdoiknow.org/archives/000442.shtml
Do your business have a DAM system or document management system? This can be a great help in this respect, particularly if it supports versioning, as this can also eliminate duplicate files and provide document history for governance purposes. You will still have similar issues with naming but most DAM systems have decent search engines.
Naming standards can be very different depending on what you do. For example, if you produce catalogs or flyers as a repeat business for a client and there is some reuse of assets, it probably makes mosts sense to inherit at least some of the name from the client i.e. using product SKU as part of the name. If you are constantly doing new and custom work, you are probably better off using a client-docket-page-position style naming standard and organizational hierarchy as you might use in a legal or medical practice or a publishing environment.
Our company sells DAM systems and we actually offer a a 1 day consultation that we call The DAM Primer to address these issues. We call it a consultation as opposed to a course, because it really depends on the client needs as to what makes sense as far as a naming standard. We usually discuss a couple of common methods and then listen to the client to help develop a standard appropriate for their workflow. We also address metadata in this consultation. We recently did this consultation with a library, and learned almost as much as we taught.